Can I use OptimizeMember Plugin with the new OptimizePress Version 3?

OptimizeMember is tied in with OP2 which includes the email integrations for OptimizeMember. If you are using OptimizeMember and are utilizing the email integrations in OP2 for that purpose, then you’ll need to keep OP2 activated. 

OptimizeMember will not work without OP2 being active on your site anyways so just make sure you keep the OP2 plugin and OptimizeMember both activated.To use OptimizeMember and protect pages created with OP3, make sure OP2, and OptimizeMember are active, and then you can go to “ pages > all pages”, click "Edit" next to the page you want to set membership settings for, and then select the OptimizeMember Options on the right side of the normal WordPress editor.

As of August 3rd, 2020 we now have integration with OptimizeMember Levels and Packages built into the OptimizeCheckouts plugin, so we recommend using the OptimizeCheckouts plugin to sell access to your courses (subscriptions are coming soon to the checkouts plugin).

Specific features for Membership sites are on the roadmap for OP3 however those will come later in the roadmap. In order to build the best membership features possible, it will take some time to develop those as our primary focus so far is with the marketing, checkouts, and funnel builder. We should have a new membership plugin specifically for OP3 this year (2020), but we are unable to provide an accurate timescale at this time as plugin development is ongoing. 
If you have any questions about this please reach out to us and we'll be happy to help.