Change is correct, but if it doesn't explicitly fix anything, I personally wouldn't bother.
See what kde-i18n-doc say

(you can add the Localization group too)

I would suggest kcm5_joystick in order to be future-proof.

In D10838#230049, @ltoscano wrote:

(you can add the Localization group too)

I would suggest kcm5_joystick in order to be future-proof.

Okay. Had proposed just "kcm" as the majority of existing catalogs is prefixed like that (consistency), and just a few have kcm5, so any next-gen plasma6 versions would need to bump all to kcm6 anyway to avoid conflicts, but might not hurt to apply versioning already now when touching anyway, so people get used to the concept :)

Historical note: the few kcm catalogs called kcm5_<foo> have been renamed by me to avoid conflict with the files with kde-runtime, which is co-installable with KF5. While this is not going to be a problem for the transition between KF5 and KF6, we can never be sure that we won't have some KCM required at the same time in both versions, so better be safe with a small change now (given that we need to rename the catalog anyway). Same for any future KCM :)