3.1.5 fixes a bug introduced in 3.1.3 where a Get operation on a binary file that is added and then branched causes the client to attempt to translate EOLs in the file, causing the Get to fail. The fix was applied to both the server and the client.
See http://support.sourcegear.com/viewtopic.php?t=4918 for the 3.1.3 Release Notes.
3.1.5 Release Notes
Moderator: SourceGear