Except when LR is part off a CC subscription, according to Adobe customer sales support if you cancel your CC subscription you also lose the ability to update your current version of LR thereafter with any future update releases for that version.
Pretty strange I thought because the downloaded install executable package should be the same as a perpetual version or so I though, however they must have a special CC version of LR with code to check subscription validity from within LR.
Brian.
My understanding (which may be imperfect as it is mainly gleaned from this chatroom), is that if you take out CC, the version of Lightroom you install will be pretty well identical to the latest perpetual version. But it will be activated with the CC registration key rather than the one you currently use.
If, at some future date, you decide to stop your CC subscription, your CC version of Lightroom will continue to work for a few weeks after your last payment but will then be disabled.
There should then be no reason why you cannot re-activate (re-installing if necessary) your old version of Lightroom with your original perpetual licence activation key. You should also, then, be able to upgrade it to the latest version at the normal perpetual version upgrade price.
The only word of caution is that Adobe (in common with some other software houses) may limit the number of version upgrades you can skip. Purely hypothetically, you may find that if your last perpetual version was LR4, then they may allow you to upgrade to LR6 at the upgrade price but, if by the time that you opt-out of CC we are up to, say, LR8, then you may have to buy at the full, rather than upgrade, price.