Every place you said "should" is actually "must" otherwise how can anything work? Clearly the next version MUST be able to read the stored data of the current v

Every place you said "should" is actually "must" otherwise how can anything work? Clearly the next version MUST be able to read the stored data of the current version and just as clearly the next version MUST write data that can be read by the current version. If not then releasing the software is totally impossible.