Any project from Web Framework 1.0 should be able to transition to Web Framework 2.0. How much effort will be required will of course vary. However, this is a cost of doing business. We have not gone back to versions of Xojo prior to the current major release and patched either. If someone using a build from 2016 said they can no longer build apps for Mac because that release doesn’t build 64 bit, we would tell them to upgrade to the latest version. That upgrade might involve them having to deal with other issues because things to change as well know very well.
Yes transitioning from Web Framework 1.0 to 2.0 isn’t as simple as opening the project and looking for things that have changed. You WILL have compile errors that you WILL have to fix before you can run. So there is a cost, but it is a one-time cost. It’s a cost of doing business. While it could be argued that us patching old versions is also a cost of doing business, we almost never get asked to do that. As a result, we don’t make a habit of doing it. Web Framework 1.0 has also been around for a long time now so if there were any showstoppers, we’d likely know about them. Having said that, some day far down the road, something may come up making Web Framework 1.0 unusable with the then current versions of various web browsers. Hopefully, no one will have waited that long to transition.
While I understand the concern, I strongly urge you each to wait until you have a pre-release or actual release to try. Then you can see how big of a one-time job you have in front of you.
FWIW, I have been converting a desktop app to a Web Framework 2.0 app and now that I have recreated the layouts, because both are API 2.0 compliant, I can just copy and paste code between the two projects will little to no modification.