I just upgraded from 2.0.5.1 to 2.1.0.9
The problem is that the resX files are outdated and the regenresx.exe.config file has not been upgraded, so older resX files are "updated" to version 2.0.5.1 instead of the current 2.1.0.9.
regenresx.exe.config.2109_1178.zip