no, the net40.sln file was created at the time when we copied the csproj files as net40.csproj to keep the net 4.0 build target for legacy purposes, then we changed the build targets in the main .csproj files to use net 4.5. therefore no change was needed in the mojoportal.sln at that time, but the new (at that time) net40.sln had to be changed to point to new (at the time) net40.csproj file names
so we had multiple sets of projects and .sln that referenced the same mostly .cs files but the build targets were different and some conditional compilation was used to account for unsupported things in older framework
the main up to date files have no reference to any framework version in their file names, ones with a name like that were created to support legacy framework versions but are no longer supported, and as of today the legacy .sln files have been removed from the repository