We recently changed the format of new objects written in the journal: D7003
However, `offset_bytes` is going to be renamed to simply `offset` in the model, as we are getting rid of the numeric `offset`. However, this will introduce yet another change to the journal format, and a somewhat confusing one.
What should we do about this?
1. keep existing objects as-is, with a mix of `offset_bytes`, a numeric `offset`, and bytes `offset`
2. keep it as-is, with a mix of `offset_bytes` and a numeric `offset`
3. rewrite every object to use a bytes `offset`
Option 1 is the hardest on future consumers, and option 3 has the highest risk for corrupting existing data. Option 2 is a middle ground.