Do the Internet Explorer Plugin and Desktop Client need to be upgraded to match the QlikView Server version?

[Daniele_Purrone]

Are unaligned versions supported? Is it supported to have a client version connecting to a different server version? 

Do customers need to update all the Desktop clients and IE plugins every time the server is upgraded?

Environment:

QlikView 

Qlik only supports the same build version between QlikView Server and QlikView Desktop / IE-plugin as QlikView is tested only with aligned versions of the software. This means that we cannot guarantee the functionality of the product when connecting from a different client version.
This is extremely important for major versions (for instance Qlikview 11.20 and QlikView 12), but also for service releases (for instance: QlikView 12.10 SR1 vs. 12.10 SR2).

Not keeping the versions aligned might result in dashboards not looking as expected, connection problems and general client instability.
Furthermore, having users connecting from outdated versions of the IE plugin has been known to cause the server to become unstable as well.

Any unaligned environment will not be supported by Qlik.