Updating to Plesk Onyx, will the manually added PHP Redis extension be working after the update? Or would we have re-configure redis using the one that comes with Plesk Onyx?
It is not really that you need to recompile or use a more up-to-date redis extension: as long as Redis does not change drastically (and it did not), the "old" extension will do the trick.
However, there is one major problem when using the "old" extension: compatibility, when upgrading.
In essence, it is best to do the following in an upgrade process:
a) de-activate the "old" extension before starting the upgrade and note that
- all relevant files, entries and settings (related to the "old" extension) should be removed properly,
- it is a good idea to "backup" all those files and settings,
and the code responsible for connecting to Redis, existing in php scripts of specific applications and websites, can be left unchanged during upgrade,
b) upgrade to Onyx and activate the default (new) Redis extension,
and that is all, it should do the trick.
This way, you would prevent a conflict between two Redis extensions (the old and the new one), while adopting the new default package and hence preventing future compatibility issues.
Why bother? Well, technically there is no need to "mess with the extensions", as long as one leaves one of the extensions inactive.
Nevertheless, during upgrade, leaving the "old" extension active can lead to unpredictable outcomes, so I would recommend to follow the steps above.
Hope the above helps a bit.
Regards......