I ugraded from version 1.25.0 built from source, the process did not go well. I had to delete the database and all files from 1.25.0. Reinstall 1.26.2, re-enter all my cameras etc.
AMD Phenom(tm) II X4 970 - Ubuntu 11.10 x64
Linux zm 3.0.0-12-server #20-Ubuntu SMP Fri Oct 7 16:36:30 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
Issues encountered;
Load configuration errors - found 216 items expected 218
Version mismatches
zumupdate.pl updated the database fine but zm would not load at all after that so I restore the back db, 1.26.2 would run but complained of version mismatch.
Missing perl libs that are present (not on make but on execution)
Small 10 camera installation in my home so I nuked all of 1.25.0 reconfigured 1.26.2 remake and installed, reconfigured from scratch and it seems this is faster and so far everything works as well if not better than 1.25.0. 1.26.2 fixed the error logs about cameras IP failing etc. All 10 cameras have been up solid far as I can tell for 18 hours.
Upgrade from 1.25.0 - Did not succeed - Still better!
Upgrade from 1.25.0 - Did not succeed - Still better!
Debian 7.8 Zoneminder 1.28.1 from source AMD FX-8370 Processor 16 gig of ram. 11 HD IP cameras.