I was doing some experiments with the Client software and reached the following conclusion: Client Software higher version then CIC version - Applications Work Client Software Lower Version then CIC Version - Does not work. I have not found any official documentation stating this and wondering what Best Practice around Client Software is and any pitfalls around upgrading client software before upgrading CIC Thank you, Scott

The rule within Development was always to keep the server backwards-compatible with Client apps within a major release, with rare exceptions. Interactive Update itself is designed to update the server first, then push out updates to Client apps. So, within a major release (2016 series, e.g.) I would expect the Client apps to function with their version level of functionality (so, might not have the latest features).

I can tell you this is not always the case. I did some testing between CIC 2015 R2 and CIC 2017 R3 and although Interaction Desktop worked fine we ran into issues. ICBM upgraded ahead of time had issues with returning recordings and reports, I suspect this could have been resolved if the database update script was run and the new crystal reports were copied to the server. Also we ran into an issue where if scripter was on 2017 R3 and connected to CIC 2015 R2 scripter would crash when logging into campaigns. All of this can be explained away by the fact that this was a huge version jump and there were fundamental changes in dialer and reports between these 2 versions. The developers, and testers, don't test for mismatched versions of the client side and server side so even though they say the server is backwards compatible it may not always the case. I would say any time you want to run a mismatched version always test in your dev environment first to hopefully uncover any of these gotchas of upgrading the client side or server side first.

Those are two different major releases. I would not expect full backwards compatibility between 2017 and 2015 releases.

Backwards compatibility should work for the most part. A higher client than Server is not supported. I ran 4.0 SU6 IC client against a 2015RX,2016Rx with no issues.

The only thing i am noticing is if the client application is higher then the Server Version, the CPU utilization on the client machine stays really high (75% to 90%) for 2 to 5 mins when launching Interaction Desktop or ICBM before dropping to a more normal range.