I updated a web map feature layer sources and overwrote the web map in portal. The web map was part of a web app and was originally saved using the map viewer classic. When I overwrite the web map with ArcPro (3.3) it overwritten it using the new map viewer. Now the web app that used the old web map won’t load. I have tried updating the web app json pointing to the old web map, but it still is broken. Is there a way to fix it and recover the web app?
The new map viewer is not compatible with older apps like the Web AppBuilder. I believe the WAB is based on JS API 3.x and the new map viewer is based on JS API 4.x. If you have been editing the JSON you may not be able to recover the web app.