I use Openfire 3.4.5 with Spark 2.5.8 and FreeBSD.
The problem is with cyrillic symbols with ICQ transport - with encoding set to “windows-1251” i can see what is sent to me ok, but people see wrong symbols when i write to them. With different encoding cyrillic symbols are broken at the both sides.
It is possible to connect to AIM using standard ICQ login and password - but in this case cyrillic symbols are broken at the both sides, even despite there is no encoding option for AIM transport at all.