John:
In general Informix servers and clients are fully forward and backward compatible within limits. Any client compiled with an ESQL/C v7.30 or later or CSDK v2.80 or later will connect and work just fine against any Informix engine v7.24 or later (though if compiled dynamically the applications will need access to the shared library versions they were compiled with).
There were library changes between ESQL/C v7.24 and v7.30 that can cause problems with connecting those earlier executables with engine versions 7.30 and later. Those apps need to be recompiled even if compiled static to be able to connect and work reliably. This was caused by the incorporation of the Illustra code in v7.30 of the engine that required library changes that are not backward compatible.
The only other caveat is that software compiled with older CSDK versions will not be able to take advantage of newer features. For example, CSDK prior to 4.10 did not have support for Connection Manager and so can only use CM in proxy mode to connect to a server (so all communications goes through the CM instance rather than reconnecting directly to the target server). You may not have access to newer data types which should not be an issue. Finally, CSDK versions prior to 4.70 cannot take advantage of the transaction survival feature.
So, very short answer is: not a problem unless.....
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Art S. Kagel, President and Principal Consultant
ASK Database Management Corp.
www.askdbmgt.com------------------------------
Original Message:
Sent: Tue December 15, 2020 09:16 AM
From: John Smith
Subject: Compatibility
Hi
Can a version of Informix work with anterior clients? for example a existing parameter on the informix engine to deal with these clients ,
or do we have to upgrade also the client part (cdsk) to a compatible version also
Thanks in advance
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John Smith
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#Informix