diff --git a/lib/lyx2lyx/LyX.py b/lib/lyx2lyx/LyX.py
index f1fcf2e403..18088a4dea 100644
--- a/lib/lyx2lyx/LyX.py
+++ b/lib/lyx2lyx/LyX.py
@@ -401,7 +401,7 @@ class LyX_base:
             self.body[i] = self.body[i].decode(self.encoding)
 
         # Read document body
-        while 1:
+        while True:
             line = self.input.readline().decode(self.encoding)
             if not line:
                 break
@@ -767,7 +767,7 @@ class LyX_base:
 
 #        toc_par = []
 #        i = 0
-#        while 1:
+#        while True:
 #            i = find_tokens(self.body, sections, i)
 #            if i == -1:
 #                break
diff --git a/lib/lyx2lyx/lyx_0_12.py b/lib/lyx2lyx/lyx_0_12.py
index 6cbd145fb5..b742dd5272 100644
--- a/lib/lyx2lyx/lyx_0_12.py
+++ b/lib/lyx2lyx/lyx_0_12.py
@@ -26,7 +26,7 @@ def space_before_layout(document):
     " Remove empty line before \\layout. "
     lines = document.body
     i = 2 # skip first layout
-    while 1:
+    while True:
         i = find_token(lines, '\\layout', i)
         if i == -1:
             break
@@ -41,7 +41,7 @@ def formula_inset_space_eat(document):
     " Remove space after inset formula."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset Formula", i)
         if i == -1:
             break
@@ -56,7 +56,7 @@ def update_tabular(document):
     lines = document.body
     lyxtable_re = re.compile(r".*\\LyXTable$")
     i = 0
-    while 1:
+    while True:
         i = find_re(lines, lyxtable_re, i)
         if i == -1:
             break
@@ -108,7 +108,7 @@ def update_inset_label(document):
     " Update inset Label."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, '\\begin_inset Label', i)
         if i == -1:
             return
@@ -120,7 +120,7 @@ def update_latexdel(document):
     " Update inset LatexDel."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, '\\begin_inset LatexDel', i)
         if i == -1:
             return
@@ -163,7 +163,7 @@ def remove_cursor(document):
     lines = document.body
     i = 0
     cursor_re = re.compile(r'.*(\\cursor \d*)')
-    while 1:
+    while True:
         i = find_re(lines, cursor_re, i)
         if i == -1:
             break
@@ -176,7 +176,7 @@ def remove_empty_insets(document):
     " Remove empty insets."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, '\\begin_inset ', i)
         if i == -1:
             break
@@ -190,7 +190,7 @@ def remove_formula_latex(document):
     " Remove formula latex."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, '\\latex formula_latex ', i)
         if i == -1:
             break
@@ -268,7 +268,7 @@ def update_latexaccents(document):
     " Update latex accent insets."
     body = document.body
     i = 1
-    while 1:
+    while True:
         i = find_token(body, '\\i ', i)
         if i == -1:
             return
@@ -297,7 +297,7 @@ def obsolete_latex_title(document):
     " Replace layout Latex_Title with Title."
     body = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(body, '\\layout', i)
         if i == -1:
             return
@@ -313,7 +313,7 @@ def remove_inset_latex(document):
     body = document.body
 
     i = 0
-    while 1:
+    while True:
         i = find_token(body, '\\begin_inset Latex', i)
         if i == -1:
             return
diff --git a/lib/lyx2lyx/lyx_1_0.py b/lib/lyx2lyx/lyx_1_0.py
index cffa2abe39..d3f65c51de 100644
--- a/lib/lyx2lyx/lyx_1_0.py
+++ b/lib/lyx2lyx/lyx_1_0.py
@@ -26,7 +26,7 @@ def obsolete_latex_title(document):
 
     body = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(body, '\\layout', i)
         if i == -1:
             return
@@ -43,7 +43,7 @@ def update_tabular(document):
     lines = document.body
     lyxtable_re = re.compile(r".*\\LyXTable$")
     i = 0
-    while 1:
+    while True:
         i = find_re(lines, lyxtable_re, i)
         if i == -1:
             break
diff --git a/lib/lyx2lyx/lyx_1_1_5.py b/lib/lyx2lyx/lyx_1_1_5.py
index 304ff7a48e..6f553649d5 100644
--- a/lib/lyx2lyx/lyx_1_1_5.py
+++ b/lib/lyx2lyx/lyx_1_1_5.py
@@ -40,7 +40,7 @@ def replace_protected_separator(document):
     " Replace protected separator. "
     lines = document.body
     i=0
-    while 1:
+    while True:
         i = find_token(lines, "\\protected_separator", i)
         if i == -1:
             break
@@ -65,7 +65,7 @@ def merge_formula_inset(document):
     " Merge formula insets. "
     lines = document.body
     i=0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset Formula", i)
         if i == -1: break
         if lines[i+1] in math_env:
@@ -79,7 +79,7 @@ def update_tabular(document):
     lines = document.body
     lyxtable_re = re.compile(r".*\\LyXTable$")
     i=0
-    while 1:
+    while True:
         i = find_re(lines, lyxtable_re, i)
         if i == -1:
             break
@@ -111,7 +111,7 @@ def update_toc(document):
     " Update table of contents. "
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines,
                        '\\begin_inset LatexCommand \\tableofcontents', i)
         if i == -1:
@@ -158,7 +158,7 @@ def remove_space_in_units(document):
 
     for margin in margins:
         i = 0
-        while 1:
+        while True:
             i = find_token(lines, margin, i)
             if i == -1:
                 break
@@ -174,7 +174,7 @@ def latexdel_getargs(document, i):
     lines = document.body
 
     # play safe, clean empty lines
-    while 1:
+    while True:
         if lines[i]:
             break
         del lines[i]
@@ -191,7 +191,7 @@ def latexdel_getargs(document, i):
     del lines[i:j + 1]
 
     # play safe, clean empty lines
-    while 1:
+    while True:
         if lines[i]:
             break
         del lines[i]
@@ -212,7 +212,7 @@ def update_ref(document):
     " Update reference inset. "
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, '\\begin_inset LatexCommand', i)
         if i == -1:
             return
@@ -230,7 +230,7 @@ def update_latexdel(document):
     lines = document.body
     i = 0
     latexdel_re = re.compile(r".*\\begin_inset LatexDel")
-    while 1:
+    while True:
         i = find_re(lines, latexdel_re, i)
         if i == -1:
             return
diff --git a/lib/lyx2lyx/lyx_1_1_6_0.py b/lib/lyx2lyx/lyx_1_1_6_0.py
index dd6112423f..6c099ae772 100644
--- a/lib/lyx2lyx/lyx_1_1_6_0.py
+++ b/lib/lyx2lyx/lyx_1_1_6_0.py
@@ -26,7 +26,7 @@ def update_tabular(document):
     " Update tabular to version 1 (xml like syntax). "
     lines = document.body
     i=0
-    while 1:
+    while True:
         i = find_re(lines, lyxtable_re, i)
         if i == -1:
             break
diff --git a/lib/lyx2lyx/lyx_1_1_6_3.py b/lib/lyx2lyx/lyx_1_1_6_3.py
index 4c8154797f..5090314cd8 100644
--- a/lib/lyx2lyx/lyx_1_1_6_3.py
+++ b/lib/lyx2lyx/lyx_1_1_6_3.py
@@ -39,7 +39,7 @@ def update_tabular(document):
     regexp = re.compile(r'^\\begin_inset\s+Tabular')
     lines = document.body
     i=0
-    while 1:
+    while True:
         i = find_re(lines, regexp, i)
         if i == -1:
             break
diff --git a/lib/lyx2lyx/lyx_1_2.py b/lib/lyx2lyx/lyx_1_2.py
index e04a4e47a2..b697a918c5 100644
--- a/lib/lyx2lyx/lyx_1_2.py
+++ b/lib/lyx2lyx/lyx_1_2.py
@@ -146,7 +146,7 @@ def remove_oldfloat(document):
     " Change \begin_float .. \end_float into \begin_inset Float .. \end_inset"
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_float", i)
         if i == -1:
             break
@@ -215,7 +215,7 @@ def remove_pextra(document):
     lines = document.body
     i = 0
     flag = 0
-    while 1:
+    while True:
         i = find_re(lines, pextra_type2_rexp, i)
         if i == -1:
             break
@@ -258,7 +258,7 @@ def remove_pextra(document):
         j = get_next_paragraph(lines, i, document.format + 1)
 
         count = 0
-        while 1:
+        while True:
             # collect more paragraphs to the minipage
             count = count+1
             if j == -1 or not check_token(lines[j], "\\layout"):
@@ -301,12 +301,12 @@ def remove_oldert(document):
                  ""]
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_tokens(lines, ["\\latex latex", "\\layout LaTeX"], i)
         if i == -1:
             break
         j = i+1
-        while 1:
+        while True:
             # \end_inset is for ert inside a tabular cell. The other tokens
             # are obvious.
             j = find_tokens(lines, ["\\latex default", "\\layout", "\\begin_inset", "\\end_inset", "\\end_float", "\\the_end"],
@@ -327,7 +327,7 @@ def remove_oldert(document):
             new = ['\layout %s' % document.default_layout, "", ""]
 
         k = i+1
-        while 1:
+        while True:
             k2 = find_re(lines, ert_rexp, k, j)
             inset = hfill = specialchar = 0
             if k2 == -1:
@@ -399,7 +399,7 @@ def remove_oldert(document):
 
     # Delete remaining "\latex xxx" tokens
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\latex ", i)
         if i == -1:
             break
@@ -410,7 +410,7 @@ def remove_oldertinset(document):
     " ERT insert are hidden feature of lyx 1.1.6. This might be removed in the future."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset ERT", i)
         if i == -1:
             break
@@ -445,7 +445,7 @@ def combine_ert(document):
     " Combine ERT paragraphs."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset ERT", i)
         if i == -1:
             break
@@ -490,7 +490,7 @@ def remove_figinset(document):
     " Remove figinset."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset Figure", i)
         if i == -1:
             break
@@ -564,7 +564,7 @@ def update_tabular(document):
     regexp = re.compile(r'^\\begin_inset\s+Tabular')
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_re(lines, regexp, i)
         if i == -1:
             break
@@ -697,7 +697,7 @@ def update_longtables(document):
     regexp = re.compile(r'^\\begin_inset\s+Tabular')
     body = document.body
     i = 0
-    while 1:
+    while True:
         i = find_re(body, regexp, i)
         if i == -1:
             break
@@ -766,7 +766,7 @@ def fix_oldfloatinset(document):
     " Figure insert are hidden feature of lyx 1.1.6. This might be removed in the future."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset Float ", i)
         if i == -1:
             break
@@ -780,7 +780,7 @@ def change_listof(document):
     " Change listof insets."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset LatexCommand \\listof", i)
         if i == -1:
             break
@@ -793,7 +793,7 @@ def change_infoinset(document):
     " Change info inset."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset Info", i)
         if i == -1:
             break
diff --git a/lib/lyx2lyx/lyx_1_3.py b/lib/lyx2lyx/lyx_1_3.py
index 195f0dcbac..35f04db8c4 100644
--- a/lib/lyx2lyx/lyx_1_3.py
+++ b/lib/lyx2lyx/lyx_1_3.py
@@ -54,7 +54,7 @@ def change_insetgraphics(document):
     " Change inset Graphics."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "\\begin_inset Graphics", i)
         if i == -1:
             break
@@ -113,7 +113,7 @@ def change_tabular(document):
     " Change tabular."
     lines = document.body
     i = 0
-    while 1:
+    while True:
         i = find_token(lines, "<column", i)
         if i == -1:
             break
diff --git a/lib/lyx2lyx/lyx_1_4.py b/lib/lyx2lyx/lyx_1_4.py
index 29abc53bfa..f88c9a8dee 100644
--- a/lib/lyx2lyx/lyx_1_4.py
+++ b/lib/lyx2lyx/lyx_1_4.py
@@ -105,7 +105,7 @@ def del_token(lines, token, start, end):
 def remove_color_default(document):
     " Remove \color default"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\color default", i)
         if i == -1:
             return
@@ -179,7 +179,7 @@ def revert_spaces(document):
     " \InsetSpace ~ -> \SpecialChar ~"
     regexp = re.compile(r'(.*)(\\InsetSpace\s+)(\S+)')
     i = 0
-    while 1:
+    while True:
         i = find_re(document.body, regexp, i)
         if i == -1:
             break
@@ -236,7 +236,7 @@ def revert_eqref(document):
     "\\begin_inset LatexCommand \\eqref -> ERT"
     regexp = re.compile(r'^\\begin_inset\s+LatexCommand\s+\\eqref')
     i = 0
-    while 1:
+    while True:
         i = find_re(document.body, regexp, i)
         if i == -1:
             break
@@ -264,7 +264,7 @@ def revert_bibtex(document):
 def remove_insetparent(document):
     " Remove \lyxparent"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset LatexCommand \\lyxparent", i)
         if i == -1:
             break
@@ -276,7 +276,7 @@ def convert_external(document):
     external_rexp = re.compile(r'\\begin_inset External ([^,]*),"([^"]*)",')
     external_header = "\\begin_inset External"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, external_header, i)
         if i == -1:
             break
@@ -311,7 +311,7 @@ def revert_external_1(document):
     " Revert inset External."
     external_header = "\\begin_inset External"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, external_header, i)
         if i == -1:
             break
@@ -336,7 +336,7 @@ def revert_external_2(document):
     " Revert inset External. (part II)"
     draft_token = '\tdraft'
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_inset External', i)
         if i == -1:
             break
@@ -354,7 +354,7 @@ def convert_comment(document):
     " Convert \\layout comment"
     i = 0
     comment = "\\layout Comment"
-    while 1:
+    while True:
         i = find_token(document.body, comment, i)
         if i == -1:
             return
@@ -365,7 +365,7 @@ def convert_comment(document):
                         '\\layout %s' % document.default_layout]
         i = i + 7
 
-        while 1:
+        while True:
                 old_i = i
                 i = find_token(document.body, "\\layout", i)
                 if i == -1:
@@ -418,7 +418,7 @@ def convert_comment(document):
 def revert_comment(document):
     " Revert comments"
     i = 0
-    while 1:
+    while True:
         i = find_tokens(document.body, ["\\begin_inset Comment", "\\begin_inset Greyedout"], i)
 
         if i == -1:
@@ -437,7 +437,7 @@ def add_end_layout(document):
     i = i + 1
     struct_stack = ["\\layout"]
 
-    while 1:
+    while True:
         i = find_tokens(document.body, ["\\begin_inset", "\\end_inset", "\\layout",
                                 "\\begin_deeper", "\\end_deeper", "\\the_end"], i)
 
@@ -504,7 +504,7 @@ def add_end_layout(document):
 def rm_end_layout(document):
     " Remove \end_layout"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\end_layout', i)
 
         if i == -1:
@@ -535,7 +535,7 @@ def rm_tracking_changes(document):
 def rm_body_changes(document):
     " Remove body changes."
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\change_", i)
         if i == -1:
             return
@@ -546,7 +546,7 @@ def rm_body_changes(document):
 def layout2begin_layout(document):
     " \layout -> \begin_layout "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\layout', i)
         if i == -1:
             return
@@ -558,7 +558,7 @@ def layout2begin_layout(document):
 def begin_layout2layout(document):
     " \begin_layout -> \layout "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_layout', i)
         if i == -1:
             return
@@ -578,7 +578,7 @@ def convert_table_valignment_middle(document):
     " Convert table  valignment, center -> middle"
     regexp = re.compile(r'^\\begin_inset\s+Tabular')
     i = 0
-    while 1:
+    while True:
         i = find_re(document.body, regexp, i)
         if i == -1:
             return
@@ -602,7 +602,7 @@ def revert_valignment_middle(document):
     " Convert table  valignment, middle -> center"
     regexp = re.compile(r'^\\begin_inset\s+Tabular')
     i = 0
-    while 1:
+    while True:
         i = find_re(document.body, regexp, i)
         if i == -1:
             return
@@ -677,7 +677,7 @@ parskip}
     attribute_values = ['default', 'default', 'default', 'default',
                         'default', 'default', 'default', 'none', document.language]
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_layout", i)
         if i == -1:
             return
@@ -835,7 +835,7 @@ parskip}
 def convert_note(document):
     " Convert Notes. "
     i = 0
-    while 1:
+    while True:
         i = find_tokens(document.body, ["\\begin_inset Note",
                                 "\\begin_inset Comment",
                                 "\\begin_inset Greyedout"], i)
@@ -850,7 +850,7 @@ def revert_note(document):
     " Revert Notes. "
     note_header = "\\begin_inset Note "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, note_header, i)
         if i == -1:
             break
@@ -862,7 +862,7 @@ def revert_note(document):
 def convert_box(document):
     " Convert Boxes. "
     i = 0
-    while 1:
+    while True:
         i = find_tokens(document.body, ["\\begin_inset Boxed",
                                 "\\begin_inset Doublebox",
                                 "\\begin_inset Frameless",
@@ -880,7 +880,7 @@ def revert_box(document):
     " Revert Boxes."
     box_header = "\\begin_inset Box "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, box_header, i)
         if i == -1:
             break
@@ -892,7 +892,7 @@ def revert_box(document):
 def convert_collapsable(document):
     " Convert collapsed insets. "
     i = 0
-    while 1:
+    while True:
         i = find_tokens_exact(document.body, ["\\begin_inset Box",
                                 "\\begin_inset Branch",
                                 "\\begin_inset CharStyle",
@@ -909,7 +909,7 @@ def convert_collapsable(document):
         # If, however, we find a line starting '\begin_layout'
         # (_always_ present) then break with a warning message
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i] == "collapsed false"):
                 document.body[i] = "status open"
                 break
@@ -927,7 +927,7 @@ def convert_collapsable(document):
 def revert_collapsable(document):
     " Revert collapsed insets. "
     i = 0
-    while 1:
+    while True:
         i = find_tokens_exact(document.body, ["\\begin_inset Box",
                                 "\\begin_inset Branch",
                                 "\\begin_inset CharStyle",
@@ -944,7 +944,7 @@ def revert_collapsable(document):
         # If, however, we find a line starting '\begin_layout'
         # (_always_ present) then break with a warning message
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i] == "status open"):
                 document.body[i] = "collapsed false"
                 break
@@ -963,7 +963,7 @@ def revert_collapsable(document):
 def convert_ert(document):
     " Convert ERT. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset ERT", i)
         if i == -1:
             break
@@ -972,7 +972,7 @@ def convert_ert(document):
         # If, however, we find a line starting '\begin_layout'
         # (_always_ present) then break with a warning message
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i] == "status Open"):
                 document.body[i] = "status open"
                 break
@@ -993,7 +993,7 @@ def convert_ert(document):
 def revert_ert(document):
     " Revert ERT. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset ERT", i)
         if i == -1:
             break
@@ -1002,7 +1002,7 @@ def revert_ert(document):
         # If, however, we find a line starting '\begin_layout'
         # (_always_ present) then break with a warning message
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i] == "status open"):
                 document.body[i] = "status Open"
                 break
@@ -1028,7 +1028,7 @@ def convert_minipage(document):
     inner_pos = ["c","t","b","s"]
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Minipage", i)
         if i == -1:
             return
@@ -1199,7 +1199,7 @@ def revert_breaks(document):
 
     # Convert the insets
     i = 0
-    while 1:
+    while True:
         i = find_tokens(document.body, tokens, i)
         if i == -1:
             return
@@ -1554,7 +1554,7 @@ def convert_frameless_box(document):
     pos = ['t', 'c', 'b']
     inner_pos = ['c', 't', 'b', 's']
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_inset Frameless', i)
         if i == -1:
             return
@@ -1733,7 +1733,7 @@ def convert_frameless_box(document):
 def remove_branches(document):
     " Remove branches. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.header, "\\branch", i)
         if i == -1:
             break
@@ -1745,7 +1745,7 @@ def remove_branches(document):
         del document.header[i:j+1]
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Branch", i)
         if i == -1:
             return
@@ -1760,7 +1760,7 @@ def remove_branches(document):
         # If, however, we find a line starting '\layout'
         # (_always_ present) then break with a warning message
         collapsed_found = 0
-        while 1:
+        while True:
             if (document.body[i][:9] == "collapsed"):
                 del document.body[i]
                 collapsed_found = 1
@@ -1821,7 +1821,7 @@ def revert_bibtopic(document):
 def convert_float(document):
     " Convert sideway floats. "
     i = 0
-    while 1:
+    while True:
         i = find_token_exact(document.body, '\\begin_inset Float', i)
         if i == -1:
             return
@@ -1829,7 +1829,7 @@ def convert_float(document):
         # If, however, we find a line starting '\begin_layout'
         # (_always_ present) then break with a warning message
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i][:4] == "wide"):
                 document.body.insert(i + 1, 'sideways false')
                 break
@@ -1843,7 +1843,7 @@ def convert_float(document):
 def revert_float(document):
     " Revert sideways floats. "
     i = 0
-    while 1:
+    while True:
         i = find_token_exact(document.body, '\\begin_inset Float', i)
         if i == -1:
             return
@@ -1883,7 +1883,7 @@ def convert_graphics(document):
     """ Add extension to documentnames of insetgraphics if necessary.
     """
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Graphics", i)
         if i == -1:
             return
@@ -1924,7 +1924,7 @@ def convert_names(document):
 
     i = 0
 
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_layout Author", i)
         if i == -1:
             return
@@ -2092,7 +2092,7 @@ def revert_paperpackage(document):
 def convert_bullets(document):
     " Convert bullets. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.header, "\\bullet", i)
         if i == -1:
             return
@@ -2110,7 +2110,7 @@ def convert_bullets(document):
 def revert_bullets(document):
     " Revert bullets. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.header, "\\bullet", i)
         if i == -1:
             return
@@ -2235,13 +2235,13 @@ def normalize_paragraph_params(document):
                          "\\leftindent"
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_layout', i)
         if i == -1:
             return
 
         i = i + 1
-        while 1:
+        while True:
             if body[i].strip() and body[i].split()[0] not in allowed_parameters:
                 break
 
@@ -2282,7 +2282,7 @@ def convert_ert_paragraphs(document):
                           '\\emph', '\\numeric', '\\bar', '\\noun',
                           '\\color', '\\lang']
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_inset ERT', i)
         if i == -1:
             return
@@ -2294,7 +2294,7 @@ def convert_ert_paragraphs(document):
 
         # convert non-standard paragraphs to standard
         k = i
-        while 1:
+        while True:
             k = find_token(document.body, "\\begin_layout", k, j)
             if k == -1:
                 break
@@ -2314,7 +2314,7 @@ def convert_ert_paragraphs(document):
         # insert an empty paragraph before each paragraph but the first
         k = i
         first_pagraph = 1
-        while 1:
+        while True:
             k = find_token(document.body, "\\begin_layout", k, j)
             if k == -1:
                 break
@@ -2329,7 +2329,7 @@ def convert_ert_paragraphs(document):
 
         # convert \\newline to new paragraph
         k = i
-        while 1:
+        while True:
             k = find_token(document.body, "\\newline", k, j)
             if k == -1:
                 break
@@ -2347,7 +2347,7 @@ def convert_ert_paragraphs(document):
 def revert_ert_paragraphs(document):
     " Remove double paragraph breaks. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_inset ERT', i)
         if i == -1:
             return
@@ -2359,7 +2359,7 @@ def revert_ert_paragraphs(document):
 
         # replace paragraph breaks with \newline
         k = i
-        while 1:
+        while True:
             k = find_token(document.body, "\\end_layout", k, j)
             l = find_token(document.body, "\\begin_layout", k, j)
             if k == -1 or l == -1:
@@ -2370,7 +2370,7 @@ def revert_ert_paragraphs(document):
 
         # replace double \newlines with paragraph breaks
         k = i
-        while 1:
+        while True:
             k = find_token(document.body, "\\newline", k, j)
             if k == -1:
                 break
@@ -2402,7 +2402,7 @@ def convert_french(document):
     # Change language in the document body
     regexp = re.compile(r'^\\lang\s+frenchb')
     i = 0
-    while 1:
+    while True:
         i = find_re(document.body, regexp, i)
         if i == -1:
             break
@@ -2448,7 +2448,7 @@ def convert_sgml_paragraphs(document):
         return
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_layout SGML", i)
 
         if i == -1:
diff --git a/lib/lyx2lyx/lyx_1_5.py b/lib/lyx2lyx/lyx_1_5.py
index afacd26164..c1d1521276 100644
--- a/lib/lyx2lyx/lyx_1_5.py
+++ b/lib/lyx2lyx/lyx_1_5.py
@@ -61,7 +61,7 @@ def find_beginning_of_layout(lines, i):
 def revert_framed(document):
     "Revert framed notes. "
     i = 0
-    while 1:
+    while True:
         i = find_tokens(document.body, ["\\begin_inset Note Framed", "\\begin_inset Note Shaded"], i)
 
         if i == -1:
@@ -216,7 +216,7 @@ def revert_booktabs(document):
     re_bspace = re.compile(r'\s+bottomspace="[^"]+"')
     re_ispace = re.compile(r'\s+interlinespace="[^"]+"')
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Tabular", i)
         if i == -1:
             return
@@ -470,14 +470,14 @@ implemented.'''
 def revert_cs_label(document):
     " Remove status flag of charstyle label. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset CharStyle", i)
         if i == -1:
             return
         # Seach for a line starting 'show_label'
         # If it is not there, break with a warning message
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i][:10] == "show_label"):
                 del document.body[i]
                 break
@@ -504,7 +504,7 @@ key "argument"
 This must be called after convert_commandparams.
 """
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\bibitem", i)
         if i == -1:
             break
@@ -592,7 +592,7 @@ def convert_commandparams(document):
     # convert_bibitem()), but could be read in, so we convert it here, too.
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset LatexCommand", i)
         if i == -1:
             break
@@ -680,7 +680,7 @@ def convert_commandparams(document):
 def revert_commandparams(document):
     regex = re.compile(r'(\S+)\s+(.+)')
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset LatexCommand", i)
         if i == -1:
             break
@@ -738,7 +738,7 @@ def revert_nomenclature(document):
     regex = re.compile(r'(\S+)\s+(.+)')
     i = 0
     use_nomencl = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset LatexCommand nomenclature", i)
         if i == -1:
             break
@@ -789,7 +789,7 @@ def revert_printnomenclature(document):
     regex = re.compile(r'(\S+)\s+(.+)')
     i = 0
     use_nomencl = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset LatexCommand printnomenclature", i)
         if i == -1:
             break
@@ -855,7 +855,7 @@ def revert_esint(document):
 def revert_clearpage(document):
     " clearpage -> ERT "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\clearpage", i)
         if i == -1:
             break
@@ -876,7 +876,7 @@ def revert_clearpage(document):
 def revert_cleardoublepage(document):
     " cleardoublepage -> ERT "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\cleardoublepage", i)
         if i == -1:
             break
@@ -934,7 +934,7 @@ def revert_encodings(document):
 def convert_caption(document):
     " Convert caption layouts to caption insets. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_layout Caption", i)
         if i == -1:
             return
@@ -954,7 +954,7 @@ def revert_caption(document):
     " Convert caption insets to caption layouts. "
     " This assumes that the text class has a caption style. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Caption", i)
         if i == -1:
             return
@@ -1119,7 +1119,7 @@ def convert_accent(document):
     re_contents = re.compile(r'^([^\s{]+)(.*)$')
     re_accentedcontents = re.compile(r'^\s*{?([^{}]*)}?\s*$')
     i = 0
-    while 1:
+    while True:
         i = find_re(document.body, re_wholeinset, i)
         if i == -1:
             return
@@ -1452,13 +1452,13 @@ def revert_utf8plain(document):
 def revert_beamer_alert(document):
     " Revert beamer's \\alert inset back to ERT. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset CharStyle Alert", i)
         if i == -1:
             return
         document.body[i] = "\\begin_inset ERT"
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i][:13] == "\\begin_layout"):
                 # Insert the \alert command
                 document.body[i + 1] = "\\alert{" + document.body[i + 1] + '}'
@@ -1471,13 +1471,13 @@ def revert_beamer_alert(document):
 def revert_beamer_structure(document):
     " Revert beamer's \\structure inset back to ERT. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset CharStyle Structure", i)
         if i == -1:
             return
         document.body[i] = "\\begin_inset ERT"
         i = i + 1
-        while 1:
+        while True:
             if (document.body[i][:13] == "\\begin_layout"):
                 document.body[i + 1] = "\\structure{" + document.body[i + 1] + '}'
                 break
@@ -1550,7 +1550,7 @@ def revert_cv_textclass(document):
 def convert_graphics_rotation(document):
     " add scaleBeforeRotation graphics parameter. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Graphics", i)
         if i == -1:
             return
@@ -1572,7 +1572,7 @@ def convert_graphics_rotation(document):
 def revert_graphics_rotation(document):
     " remove scaleBeforeRotation graphics parameter. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Graphics", i)
         if i == -1:
             return
diff --git a/lib/lyx2lyx/lyx_1_6.py b/lib/lyx2lyx/lyx_1_6.py
index 3900dbf926..f8409a0c7b 100644
--- a/lib/lyx2lyx/lyx_1_6.py
+++ b/lib/lyx2lyx/lyx_1_6.py
@@ -972,7 +972,7 @@ def revert_pdf_options(document):
 def remove_inzip_options(document):
     "Remove inzipName and embed options from the Graphics inset"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Graphics", i)
         if i == -1:
             return
@@ -1000,7 +1000,7 @@ def convert_inset_command(document):
             LatexCommand cmd
     """
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset LatexCommand", i)
         if i == -1:
             return
@@ -1039,7 +1039,7 @@ def revert_inset_command(document):
         will not be able to recognize. Not sure what to do about that.
     """
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset CommandInset", i)
         if i == -1:
             return
@@ -1262,7 +1262,7 @@ def revert_japanese_encoding(document):
 def revert_inset_info(document):
     'Replace info inset with its content'
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_inset Info', i)
         if i == -1:
             return
@@ -1743,7 +1743,7 @@ def convert_serbocroatian(document):
 def convert_framed_notes(document):
     "Convert framed notes to boxes. "
     i = 0
-    while 1:
+    while True:
         i = find_tokens(document.body, ["\\begin_inset Note Framed", "\\begin_inset Note Shaded"], i)
         if i == -1:
             return
@@ -1820,7 +1820,7 @@ def revert_colsep(document):
 def revert_framed_notes(document):
     "Revert framed boxes to notes. "
     i = 0
-    while 1:
+    while True:
         i = find_tokens(document.body, ["\\begin_inset Box Framed", "\\begin_inset Box Shaded"], i)
 
         if i == -1:
@@ -1938,7 +1938,7 @@ def revert_nocite_key(body, start, end):
 def revert_nocite(document):
     "Revert LatexCommand nocite to ERT"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset CommandInset citation", i)
         if i == -1:
             return
@@ -2056,7 +2056,7 @@ def revert_serbianlatin(document):
 def revert_rotfloat(document):
     " Revert sideways custom floats. "
     i = 0
-    while 1:
+    while True:
         # whitespace intended (exclude \\begin_inset FloatList)
         i = find_token(document.body, "\\begin_inset Float ", i)
         if i == -1:
@@ -2119,7 +2119,7 @@ def revert_rotfloat(document):
 def revert_widesideways(document):
     " Revert wide sideways floats. "
     i = 0
-    while 1:
+    while True:
         # whitespace intended (exclude \\begin_inset FloatList)
         i = find_token(document.body, '\\begin_inset Float ', i)
         if i == -1:
@@ -2171,7 +2171,7 @@ def revert_widesideways(document):
 def revert_inset_embedding(document, type):
     ' Remove embed tag from certain type of insets'
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset %s" % type, i)
         if i == -1:
             return
@@ -2196,7 +2196,7 @@ def revert_external_embedding(document):
 def convert_subfig(document):
     " Convert subfigures to subfloats. "
     i = 0
-    while 1:
+    while True:
         addedLines = 0
         i = find_token(document.body, '\\begin_inset Graphics', i)
         if i == -1:
@@ -2236,7 +2236,7 @@ def convert_subfig(document):
 def revert_subfig(document):
     " Revert subfloats. "
     i = 0
-    while 1:
+    while True:
         # whitespace intended (exclude \\begin_inset FloatList)
         i = find_tokens(document.body, ['\\begin_inset Float ', '\\begin_inset Wrap'], i)
         if i == -1:
@@ -2740,7 +2740,7 @@ def convert_japanese_plain(document):
 def revert_pdfpages(document):
     ' Revert pdfpages external inset to ERT '
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset External", i)
         if i == -1:
             return
@@ -2842,7 +2842,7 @@ def revert_master(document):
 def revert_graphics_group(document):
     ' Revert group information from graphics insets '
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Graphics", i)
         if i == -1:
             return
@@ -2872,7 +2872,7 @@ def update_apa_styles(document):
                     "Paragraph*":      "Paragraph",
                     "Subparagraph*":   "Subparagraph"}
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_layout", i)
         if i == -1:
             return
diff --git a/lib/lyx2lyx/lyx_2_0.py b/lib/lyx2lyx/lyx_2_0.py
index bd43839ec0..243cbb8958 100644
--- a/lib/lyx2lyx/lyx_2_0.py
+++ b/lib/lyx2lyx/lyx_2_0.py
@@ -916,7 +916,7 @@ def merge_gbrief(document):
                     "Verteiler":       "cc",
                     "Gruss":           "Closing"}
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_layout", i)
         if i == -1:
             break
@@ -1332,7 +1332,7 @@ def revert_lyx_version(document):
         pass
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_inset Info', i)
         if i == -1:
             return
@@ -1481,7 +1481,7 @@ def revert_align_decimal(document):
 def convert_optarg(document):
   " Convert \\begin_inset OptArg to \\begin_inset Argument "
   i = 0
-  while 1:
+  while True:
     i = find_token(document.body, '\\begin_inset OptArg', i)
     if i == -1:
       return
@@ -1492,7 +1492,7 @@ def convert_optarg(document):
 def revert_argument(document):
   " Convert \\begin_inset Argument to \\begin_inset OptArg "
   i = 0
-  while 1:
+  while True:
     i = find_token(document.body, '\\begin_inset Argument', i)
     if i == -1:
       return
@@ -1503,7 +1503,7 @@ def revert_argument(document):
 def revert_makebox(document):
   " Convert \\makebox to TeX code "
   i = 0
-  while 1:
+  while True:
     i = find_token(document.body, '\\begin_inset Box', i)
     if i == -1:
       break
@@ -1550,7 +1550,7 @@ def revert_makebox(document):
 def convert_use_makebox(document):
   " Adds use_makebox option for boxes "
   i = 0
-  while 1:
+  while True:
     i = find_token(document.body, '\\begin_inset Box', i)
     if i == -1:
       return
@@ -1668,7 +1668,7 @@ def revert_nameref(document):
   for cmd in cmds:
     i = 0
     oldcmd = "LatexCommand " + cmd
-    while 1:
+    while True:
       # It seems better to look for this, as most of the reference
       # insets won't be ones we care about.
       i = find_token(document.body, oldcmd, i)
@@ -1705,7 +1705,7 @@ def revert_nameref(document):
 def remove_Nameref(document):
   " Convert Nameref commands to nameref commands "
   i = 0
-  while 1:
+  while True:
     # It seems better to look for this, as most of the reference
     # insets won't be ones we care about.
     i = find_token(document.body, "LatexCommand Nameref" , i)
@@ -1947,7 +1947,7 @@ def convert_rule(document):
 def revert_rule(document):
     " Revert line insets to Tex code "
     i = 0
-    while 1:
+    while True:
       i = find_token(document.body, "\\begin_inset CommandInset line" , i)
       if i == -1:
         return
@@ -2349,7 +2349,7 @@ def revert_script(document):
     " Convert subscript/superscript inset to TeX code "
     i = 0
     foundsubscript = False
-    while 1:
+    while True:
         i = find_token(document.body, '\\begin_inset script', i)
         if i == -1:
             break
diff --git a/lib/lyx2lyx/lyx_2_1.py b/lib/lyx2lyx/lyx_2_1.py
index 2e53a6fd79..fa6a224ec2 100644
--- a/lib/lyx2lyx/lyx_2_1.py
+++ b/lib/lyx2lyx/lyx_2_1.py
@@ -838,7 +838,7 @@ def revert_verbatim(document, starred = False):
                    'begin{%s}' % (latex_name),
                    '\\end_layout', '', '\\begin_layout Plain Layout', '']
 
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_layout %s" % (layout_name), i)
         if i == -1:
             return
@@ -850,7 +850,7 @@ def revert_verbatim(document, starred = False):
             continue
         # delete all line breaks insets (there are no other insets)
         l = i
-        while 1:
+        while True:
             n = find_token(document.body, "\\begin_inset Newline newline", l, j)
             if n == -1:
                 n = find_token(document.body, "\\begin_inset Newline linebreak", l, j)
@@ -898,7 +898,7 @@ def revert_verbatim(document, starred = False):
 def revert_tipa(document):
     " Revert native TIPA insets to mathed or ERT. "
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset IPA", i)
         if i == -1:
             return
diff --git a/lib/lyx2lyx/lyx_2_2.py b/lib/lyx2lyx/lyx_2_2.py
index 25c4ba06f0..6ecc878c44 100644
--- a/lib/lyx2lyx/lyx_2_2.py
+++ b/lib/lyx2lyx/lyx_2_2.py
@@ -153,7 +153,7 @@ def convert_separator(document):
         }
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_deeper", i)
         if i == -1:
             break
@@ -175,7 +175,7 @@ def convert_separator(document):
             i = i + 1
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\align", i)
         if i == -1:
             break
@@ -208,7 +208,7 @@ def convert_separator(document):
     regexp = re.compile(r'^\\begin_layout (?:(-*)|(\s*))(Separator|EndOfSlide)(?:(-*)|(\s*))$', re.IGNORECASE)
 
     i = 0
-    while 1:
+    while True:
         i = find_re(document.body, regexp, i)
         if i == -1:
             return
@@ -249,7 +249,7 @@ def revert_separator(document):
               "", "\\end_inset", ""]
 
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Separator", i)
         if i == -1:
             return
@@ -341,7 +341,7 @@ def convert_parbreak(document):
     """
     parbreakinset = "\\begin_inset Separator parbreak"
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, parbreakinset, i)
         if i == -1:
             return
@@ -366,7 +366,7 @@ def revert_parbreak(document):
     Revert latexpar separators to parbreak separators.
     """
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset Separator latexpar", i)
         if i == -1:
             return
diff --git a/lib/lyx2lyx/lyx_2_3.py b/lib/lyx2lyx/lyx_2_3.py
index d6cba52539..31368902b9 100644
--- a/lib/lyx2lyx/lyx_2_3.py
+++ b/lib/lyx2lyx/lyx_2_3.py
@@ -78,7 +78,7 @@ def revert_microtype(document):
 def convert_dateinset(document):
     ' Convert date external inset to ERT '
     i = 0
-    while 1:
+    while True:
         i = find_token(document.body, "\\begin_inset External", i)
         if i == -1:
             return