diff --git a/development/FORMAT b/development/FORMAT
index b6ca416932..4bf18da61e 100644
--- a/development/FORMAT
+++ b/development/FORMAT
@@ -8,7 +8,9 @@ changes happened in particular if possible. A good example would be
 -----------------------
 
 2019-08-06 Jürgen Spitzmüller <spitz@lyx.org>
- 	* Format incremented to 585: Add more page sizes to KOMA and memoir.
+ 	* Format incremented to 585: 
+          - Add more page sizes to KOMA and memoir.
+          - Add more font sizes to KOMA.
 
 2019-07-26 Joel Kulesza <jkulesza@gmail.com>
 	* Format incremented to 584: support for revision InsetInfo addition of
diff --git a/lib/layouts/scrclass.inc b/lib/layouts/scrclass.inc
index ab64f2d24b..55003610ac 100644
--- a/lib/layouts/scrclass.inc
+++ b/lib/layouts/scrclass.inc
@@ -8,13 +8,15 @@
 # Labeling is now used also in non-KOMA classes
 
 
-Format 77
+Format 78
 SecNumDepth             2
 TocDepth                2
 DefaultStyle            Standard
 Provides                subscript 1
 
 ClassOptions
+	FontSize             9|10|11|12|13|14|15|16|17|18|19|20
+	FontSizeFormat       fontsize=$$s
 	PageSize       a0paper|a1paper|a2paper|a3paper|a4paper|a5paper|a6paper|b0paper|b1paper|b2paper|b3paper|b4paper|b5paper|b6paper|c0paper|c1paper|c2paper|c3paper|c4paper|c5paper|c6paper|executivepaper|legalpaper|letterpaper
 End
 
diff --git a/lib/lyx2lyx/lyx_2_4.py b/lib/lyx2lyx/lyx_2_4.py
index 1f47342407..47311b67c7 100644
--- a/lib/lyx2lyx/lyx_2_4.py
+++ b/lib/lyx2lyx/lyx_2_4.py
@@ -3160,7 +3160,7 @@ def revert_pagesizes(document):
 def convert_pagesizes(document):
     " Convert to new page sizes in memoir and KOMA to options "
 
-    if document.textclass != "memoir" and document.textclass[:2] != "scr":
+    if document.textclass != "memoir" and document.textclass[:3] != "scr":
         return
 
     i = find_token(document.header, "\\use_geometry true", 0)
@@ -3183,6 +3183,38 @@ def convert_pagesizes(document):
         # Maintain use of geometry
         document.header[1] = "\\use_geometry true"
 
+def revert_komafontsizes(document):
+    " Revert new font sizes in KOMA to options "
+
+    if document.textclass[:3] != "scr":
+        return
+
+    i = find_token(document.header, "\\paperfontsize", 0)
+    if i == -1:
+        document.warning("Malformed LyX document! Missing \\paperfontsize header.")
+        return
+
+    defsizes = ["default", "10", "11", "12"]
+
+    val = get_value(document.header, "\\paperfontsize", i)
+    if val in defsizes:
+        # nothing to do
+        return
+
+    document.header[i] = "\\paperfontsize default"
+
+    fsize = "fontsize=" + val
+
+    i = find_token(document.header, "\\options", 0)
+    if i == -1:
+        i = find_token(document.header, "\\textclass", 0)
+        if i == -1:
+            document.warning("Malformed LyX document! Missing \\textclass header.")
+            return
+        document.header.insert(i, "\\options " + fsize)
+        return
+    document.header[i] = document.header[i] + "," + fsize
+
     
 
 ##
@@ -3234,7 +3266,7 @@ convert = [
            [585, [convert_pagesizes]]
           ]
 
-revert =  [[584, [revert_pagesizes]],
+revert =  [[584, [revert_pagesizes,revert_komafontsizes]],
            [583, [revert_vcsinfo_rev_abbrev]],
            [582, [revert_ChivoFont,revert_CrimsonProFont]],
            [581, [revert_CantarellFont,revert_FiraFont]],