Custom SmartApps (written in groovy), are they still valid on the new platform?

I’m late in the game on the ST news as far as the new app is concerned. Everything I read is geared towards consumer type users. But what about us power platform users?
I have multiple hand-written automations running with the legacy app. Now, I am being prompted to migrate to the new app. Will I lose the functionality of my automation programs? Will we have a new IDE?
Please de-confuse me.

They will keep working for now. Groovy isn’t slated to be retire until end of 2021.

For your custom Groovy code you need to check ASAP if they work with the new app, especially if they have any custom tile displays (that don’t work the same way). The Classic app will be disabled in a few weeks.

and then this thread on updating your Groovy code to display in the new app:

Thank you all for your replies. One follow up question, if I’m going to continue to have access to the developer tools, will I need to become a company (entity) or will ST disallow me, a simple home-owner, power user, to continue writing my own automation code?

Thanks again,

If you sign up for the new developer workspace, it’s language is confusing and says you need to part of an “organization” as if it needs to be an officially recognized company. But you can ignore that and just be your own organization and get registered. You should be able to use that for writing new SmartApps and device handlers using the new API. You have to have your own hosting for those.

And your custom Groovy code (running in the SmartThings cloud) will need to be rewritten to use the new API next year when the Groovy infrastructure (and the current IDE) is shut down as part of Phase 3 (Announcement | Changes to our Legacy SmartThings Platform).

Thank you again! That really clears up my confusion. I’ll begin to do my migration today.