Removing mongodb and redis as dependencies
No changes at all! v2 is fully compatible with v1.
Since NPM's optionalDependencies are not at all optional (they are always installed), we have some mongodb and redis modules conflicts. The only way to solve it was to remove them as optionalDependencies.
In addition to acl2 you would need to install mongodb or redis manually (if using any of those backends).
So, if using in-memory you need only npm i acl2.
If using redis backend please npm i acl2 redis.
If using MongoDB backend npm i acl2 mongodb.