[merge] Allow merging OS/2 tables of different versions
diff --git a/Lib/fontTools/merge.py b/Lib/fontTools/merge.py
index 8e212ec..fe61f94 100644
--- a/Lib/fontTools/merge.py
+++ b/Lib/fontTools/merge.py
@@ -260,9 +260,9 @@
'sTypoLineGap': max,
'usWinAscent': max,
'usWinDescent': max,
- 'ulCodePageRange1': bitwise_or,
- 'ulCodePageRange2': bitwise_or,
- 'usMaxContex': max,
+ 'ulCodePageRange1': onlyExisting(bitwise_or),
+ 'ulCodePageRange2': onlyExisting(bitwise_or),
+ 'usMaxContex': onlyExisting(max),
# TODO version 5
}