EinmalIM , ChristianGalla , Steve and M1980 : apologies on the delayed answer.
I'm prepping a FAQ which I'll link in the related posts and articles answering the common questions with the needed details. Let me already give some short answers in the meanwhile:
- App catalogs stay, they are an essential part needed to deploy SPFx solutions. Deploying Add-Ins to SharePoint Online from the app catalog will not be possible anymore once we're retired Add-Ins in April 2026
- About remote event receivers: We're investigating the options here, more information will be added to the FAQ and shared here
- About migrating data from the app webs: we're not planning a migration tool for that, using SharePoint APIs the data and setup can be read and copied over to a new location
- About SPFx for SharePoint on-premises: SPFx for on-premises will always run (far) behind given the different release models, we do understand that building with SPFx and have the same code base work across SharePoint Online and SharePoint on-premises poses challenges. Do know that Add-Ins will stay working for SharePoint on-premises after April 2026.
Microsoft