When a new version of Google Ads Editor is available, the upgrade sometimes requires you to re-download your account information. However, you always have a chance to create a backup file with your changes and comments before you install the new version.
After the upgrade is complete, download your account again and import the backup archive to find your comments and unposted changes intact.
If you want to post changes before installing the update, click Don't update when you're asked to upgrade, then post your changes. You'll be prompted to download the new version the next time you open Google Ads Editor.