The 8.x-4.6 release arrives soon after 8.x-4.5 and introduces bugfixes for 8.x-4.5.
As with any release, even though we have tested it thoroughly, please make sure to backup your data (in particular your triplestore) before upgrading.
Mark says about this release:
A lot of work has been going into this release, however we [sic; this statement only reflects Mark's opinion] don't really consider it stable yet. It might throw away data, so be sure to make a backup of all your data, triplestore, sql and files! You might need to come back to a previous state!
If you are afraid to use this here you can also take the scs_base branch, this should be rockstable.
See the full release notes for details.