As a new addon developer I have never experienced a patch day before so I was wondering how the Curse client handles it.
If I upload the 5.2 version of my addon now (or any time before 5.2 drops), will the Curse client recognise that this version is for 5.2 and not offer if for download until the user has 5.2 installed, or will I have to wait until patch day morning to upload my new version?
Similarly, with US and EU patches coming on different days, if my addon is ready for US clients on the Tuesday morning, will people on EU realms get it immediately or will it wait for the next day for them.
It's not that "smart", your best bet is to just temporarily be a bit more verbose in your description and changelog about it being "compatible with patch 5.2" so users that don't have the patch yet can stay with last 5.1 version or they know the addon will be broken (or need "load out of date" checked if there's no breaking API changes) until 5.2 lands.
To be clear, there's no automatic handling, you'll just need to inform your users.