At our company we are using a Pervasive SQL Server V8.70.014.000

 The Client software varies on all our clients. Sometimes we're using Pervasive SQL 9.10.020.00 and sometimes earlier versions. (v8.x or v9.x)

 We experience some problems in our organisation. Is this a known issue? Or are there any specific adjustements that have to be done on client side?

Many thanks,

Raf

http://www.pervasive.com/library/docs/psql/950/sgs/sgs-26-09.html discusses engine client version conflicts.  Typically, older requesters should work against newer engines, but the opposite new requesters to older engines may not work.  

As you probably know, Pervasive stop supporting version 8.7 back in December 2006.

Jose