I recently upgraded from 126.96.36.199 to 188.8.131.52 using the following instructions from Makarai:
pkg install libraw
service emby-server stop
pkg add -f https://github.com/MediaBrowser/Emby.Releases/releases/download/184.108.40.206/emby-server-freebsd_220.127.116.11_amd64.txz
service emby-server start
Upgrade went smoothly and after initial database upgrade, library scan (4 & a half hours) and reinstall of some plugins, everything worked great...
I added some more media and did a manual library scan which took around 40 minutes (18.104.22.168 would scan in ~10 mins).
I have done a couple more scans and get the same results around 40 minutes per scan. The scan gets to around 90% in about 5 minutes and then the last 10% takes the rest of the time.
Any ideas about why it takes longer?