This breaking changes page on the wiki (https://github.com/mongodb/mongo-cxx-driver/wiki/Breaking-changes-between-26compat-and-legacy) is out of date. This is a necessary resource for people looking to upgrade away from 26compat to the more feature rich legacy-1.0 release. We should audit the diff between 26compat and legacy-1.0-rc4-pre and update the breaking changes page as needed.