We use a custom workflow page in our DRA installation that uses an LDAP query that retrieves a list of organizationalUnit objects. The query worked in 10.0 but failed in 10.1. I discovered by trial and error that 10.1 limits LDAP query results to 250 objects (and of course, our query includes more objects than that). This is not mentioned in the documentation or release notes and seems to have been a change in between 10.0 and 10.1.
The search result limit in 10.0 (whatever it was) was an implicit API that changed unexpectedly when the limit was changed to 250 objects. In my case I was able to work around this limitation by modifying the query and making some other changes, but other customers may not be as adept at modifying code and changes like this can cause significant problems. Please inform customers when making these kinds of changes.