diff --git a/development/tools/separator-convert.sh b/development/tools/separator-convert.sh
new file mode 100755
index 0000000000..ceb70feaf7
--- /dev/null
+++ b/development/tools/separator-convert.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+# Lyx files converted from 2.1 to 2.2 contain parbeak and latexpar separators
+# that would not appear if the lyx file was written in 2.2 from scratch. The
+# script removes latexpar separators and transforms parbreak separators into
+# plain separators. Then it displays a diff of the resulting pdf files (requires
+# diffpdf) for manual control. All lyx files shipped with lyx should be updated
+# in this way. See #10068.
+#
+# example usage:
+# cd lib/doc
+# ../development/tools/separator-convert.sh Math.lyx
+#
+BUILD=../../build
+LYX=$BUILD/src/lyx
+cp $1 $1.old
+$LYX -E pdf2 $1.old.pdf $1
+sed -i "s/^\\\\begin_inset Separator parbreak$/\\\\begin_inset Separator plain/" $1
+sed -i "/^\\\\begin_inset Separator latexpar$/ { N; d; }" $1
+$LYX -e lyx $1
+$LYX -E pdf2 $1.pdf $1
+diffpdf $1.old.pdf $1.pdf