Ads (usually) will no longer be re-set and sent back to editorial review when tracking criteria change.
Yesterday, Google announced the release of what are dubbed “upgraded URLs” for AdWords advertisers that use tracking parameters. Upgraded URLs have been in beta for API users for months and are now rolling out globally to all users in the web interface this week.
With this change, the landing page URL and the tracking parameters that make up the destination URL will be treated separately. The separation means that making changes to your tracking won’t necessarily send your ads back into editorial review and ad history and stats remain with the ads.
You can scale tracking parameters across various levels of your accounts and set up new custom tracking parameters.