I can't open old world saved from build 7. This world was laat time saved by the border of old world. The loading states "Generating world" and tips are shown with loading bar stuck at 50%.
Device: Samsung Galaxy J7 Prime G610F
The world sample will be included as an attachment
Note: Upon converting this world to infinite it will load, but while it is an old world type it won't.
And I didn't test this out for windows 10.