If a proof has more than one version, you will be able to compare versions.
To compare proof versions
Open the proof and click the compare icon at the bottom of the screen. This icon will appear if the proof has more than one version.
The proof versions will display side-by-side. If the dimensions match exactly, smart compare is available. Comments can be added in compare mode too if the proof is in a status that allows commenting.
Tip: You can also compare two different proofs.