When adding new columns your always in danger of making the App unable to sync for the users. It would be helpful if we could put the app into a state where new columns and/or tables are ignored by devices where they have an older version of the App than the definition.
Once you have client with more than 10 users, its unprofessional to expect them to not use their App for 30mins+ whilst you add new columns. Also with a company of that size or bigger there’s always goign to be that one guy that ignores all the warnings and tried to upload data anyway.