Amid various tests I have noted the following that may save someone
some grief.

I have seen some suggestions that to use legacy applications you
could rename fbclient.dll to gds32.dll and place it in a suitable
directory. There is a danger with this.

fbclient.dll supports calls to return the version number of the
client. Some code will look at these calls which are also supported
by IB 7, and will get a version nuber of 1.5. On discovering that it
is less than version 6 it may disable IB 6 functionality. In
particular, rollback retaining may fail - and it could be some time
before you trigger the circumstances that need it.

The gds32 stub does not export the new calls so the code is likely
to detect it as IB 6 and retain the IB 6 functionality.

Recent IBX-based code will suffer from this. (Nobody said it was
compatible.)

Eric Thorniley