Hopefully in the next update. If not, then probably the next update after that. Those kinds of announcements are never made in advance. You will know as soon as anyone else does, at least anyone outside of Adobe.
Historically, a new model from Canon gets supported in the LR release following the model's announcement about 78% of the time: Re: Timing of Lightroom releases . The EOS RP was announced on 2/14/19, LR 8.2 was released on 2/12/19, and Adobe updates LR about once every 62 days, so there's a strong likelihood that the EOS RP will be supported in 8.3, which we might expect around 4/15.
(As Jim said, Adobe almost never tips its hand about releases, but the timing of releases with LR 6, 7, and 8 has been pretty consistent.)
Adobe has already released an interim beta of the DNG Converter 11.2.1 (which includes Canon EOS RP support) if you want to convert to DNG while waiting for the official LR update
Its a beta so the conversion may not be the final one that is in Lightroom 8.3 so don't discard the RAW files
This "beta" of DNG converter does not work for Canon EOS RP .CR3 files.
Are you choosing the FOLDER containing the images, but not opening the folder when setting things up in the DNG converter?
OK... GOOD NEWS! It works!
Turns out that it was pulling from a folder I used in a previous version for conversions - perhaps a beta bug -- and because the "converting" window is too short and I used medium sized path names everything I could see on the path in and out was "correct", but in reality is wrong.
I'm going to assume this is a beta problem, but they really do need to widen the conversion window.
In the meantime - it works but you may have to do a Windows search of your drive to find your converted files -- that's how i found them.
We are happy to announce Lightroom Classic 8.2.1
New camera raw file support added in this release:
You can install the updates on desktop applications via the Creative Cloud App. [CTRL/CMD]+[ALT/OPT]+[ R ] will refresh your app if the update doesn’t appear. See Keep your Lightroom version up to date and Update apps to the latest release of Adobe Creative Cloud
I am still not getting RP camera matching in Lightroom and its now November 2019. My Lightroom is up to date I've looked oin the supported camera folder and RP is not there, the "R" is but not the "RP"