diff --git a/development/FORMAT b/development/FORMAT
index 58bcc65e51..5154b0f6de 100644
--- a/development/FORMAT
+++ b/development/FORMAT
@@ -7,6 +7,10 @@ changes happened in particular if possible. A good example would be
 
 -----------------------
 
+2024-06-11 Udi Fogiel <ufogiel@lyx.org>
+	* Format incremented to 623: Remove hebrew letter document class.
+	  Old documents will be mapped to regular letter document class.
+
 2024-06-01 Jürgen Spitzmüller <spitz@lyx.org> 
 	* Format incremented to 622: Allow glue length (skip) in parskip setting.
 
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 4ad1745aa7..7356b79542 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -2546,7 +2546,6 @@ dist_layouts_DATA =\
 	layouts/graphicboxes.module \
 	layouts/hanging.module \
 	layouts/heb-article.layout \
-	layouts/heb-letter.layout \
 	layouts/hollywood.layout \
 	layouts/hpstatement.module \
 	layouts/IEEEtran.layout \
diff --git a/lib/layouts/heb-letter.layout b/lib/layouts/heb-letter.layout
deleted file mode 100644
index f009e2fc59..0000000000
--- a/lib/layouts/heb-letter.layout
+++ /dev/null
@@ -1,19 +0,0 @@
-#% Do not delete the line below; configure depends on this
-#  \DeclareLaTeXClass[letter]{Hebrew Letter}
-#  \DeclareCategory{Letters}
-# Hebrew letter textclass definition file.
-# Author: Dekel Tsur <dekel@math.tau.ac.il>
-
-Format 104
-Input letter
-
-
-Style My_Address
-	Align                 Left
-End
-
-
-Style Send_To_Address
-	Align                 Right
-End
-
diff --git a/lib/lyx2lyx/lyx_2_5.py b/lib/lyx2lyx/lyx_2_5.py
index f41b902836..2225c44e5b 100644
--- a/lib/lyx2lyx/lyx_2_5.py
+++ b/lib/lyx2lyx/lyx_2_5.py
@@ -196,6 +196,12 @@ def revert_glue_parskip(document):
     document.header[i] = "\\paragraph_separation indent"
     document.header[j] = "\\paragraph_indentation default"
 
+def convert_he_letter(document):
+    """Convert hebrew letter to letter document class"""
+
+    if document.textclass == "heb-letter":
+        document.textclass = "letter"
+
 
 ##
 # Conversion hub
@@ -204,11 +210,13 @@ def revert_glue_parskip(document):
 supported_versions = ["2.5.0", "2.5"]
 convert = [
            [621, [convert_url_escapes, convert_url_escapes2]],
-           [622, []]
+           [622, []],
+           [623, [convert_he_letter]]
           ]
 
 
-revert =  [[621, [revert_glue_parskip]],
+revert =  [[622, []],
+           [621, [revert_glue_parskip]],
            [620, [revert_url_escapes2, revert_url_escapes]]
           ]
 
diff --git a/src/version.h b/src/version.h
index ab38adf622..c26561a6d5 100644
--- a/src/version.h
+++ b/src/version.h
@@ -32,8 +32,8 @@ extern char const * const lyx_version_info;
 
 // Do not remove the comment below, so we get merge conflict in
 // independent branches. Instead add your own.
-#define LYX_FORMAT_LYX 622 // spitz: support glue length in parskip
-#define LYX_FORMAT_TEX2LYX 622
+#define LYX_FORMAT_LYX 623 // ufogiel: remove hebrew letter
+#define LYX_FORMAT_TEX2LYX 623
 
 #if LYX_FORMAT_TEX2LYX != LYX_FORMAT_LYX
 #ifndef _MSC_VER