Since JDK-8140400 the deployment code never reads sections 3 and 4 of a cached jar's cache index files. These entries contain the Jar Manifest and Jar Code Signing information for jar entries, but this info is read directly from the Jar File since JDK-8140400.
If we bump the Cache version to 606, previous versions will not be effected (cache entries created with version 606 will be invalidated when run with deployment code supporting any earlier version)