This version includes database changes. You need to log all terminals out during update.
This version of c9 increases part number maximum length from 20 to 35 chars, to accommodate CF-MOTO and a couple of other suppliers that use very large part numbers.
Minimal effort has been put into tweaking reports etc so really long part numbers will overprint / underprint depending on the specific report. Tweaks will be made gradually over time to tidy as strictly needed. Most screens have been modified where possible to display longer parts.
4.846 : is a patch that is relevant here. Looks like DB changes are so heavy in 4.845 that it messes up statistics that PostgreSQL builds up to figure out best way to grab data from DB. Result is things that normally are instantaneous like lookup a part take forever. Normally this sort of thing fixes itself eventually. But 4.846 includes commands to tell DB to explicitly regenerate stats to avoid this issue.