Weaver Xtreme 5 is a major update, with possibly some effect on existing sites. The main deisgn difference is how full width is supported. Some of the legacy full width options are no longer supported in the options. With close to 100% effectivenes, the old settings will be automatically converted to the new methods.
We’ve not seen any sites actually break, but a few have had some changes in the full width layout.
Sites most likely to see changes seem to use some custom CSS rather than Weaver Xtreme settings.
During the conversion, the old V4 settings are left untouched, so it is fairly easy to revert to. You can get it from the WP archive repository, or by using this link: https://weavertheme.com/download/9081/