The answer really depends on where your current membership plugin stores its user data. Does it use the regular WordPress database tables (users and usermeta) or its own method? If the latter, what is that method?
If you named your current plugin, it would be easier for others to tell you of their own experiences.
The current membership plugin is called “Membership by WPmudev”
I feared it might be!
Not only does that plugin not use the standard WordPress tables, it doesn’t (unless this has recently changed) provide a means of exporting user data. And because it doesn’t use standard tables, other plugins can’t be used to do this job instead.
If you can work out a way to get the data out, you could then use s2Member’s Import/Export functions to create a CSV file to import with all the data.
Otherwise, you’re going to be forced simply to install s2Member in place of Membership, and then place a Billing Modification Form (if using Pro) or Button on a page your users can access to get them to renew their membership.
You could, perhaps, use the One-Time Offers feature in General Options to automatically redirect users to this page when they first login to the site after you’ve switched over to s2Member.
I was thinking of manually migrating all my subscribers to S2member. I want to know if I can manually give them access to premium content till a specific date and then automatically send them an email to renew their membership.
If yes, then how can I do it?
You can certainly give them access manually. (You must really want to move plugins to do that!)
As for the automatic renewal email, that is not currently possible out of the box, but there is an add-on by another developer that will do that job.
This feature is, though, scheduled to be included in the next update of s2Member.
How can I manually give customers access to the data and set a deadline for the subscriptions?
If you go to the WordPress Users back-end after installing s2Member, you should be able to change their user role to one of the levels set by s2Member.
You set content restrictions by working through the s2Member back-end step by step, but specifically by following the instructions for Restriction Options. This will enable you to protect posts, pages, categories and/or tags by user role level.
As for deadlines, you have two options. One will require you to go into each user manually and set the EOT there.
Alternatively, you could use the Import/Export feature to export the list of users to CSV, then add the EOT in the relevant column in the CSV file, and then re-import that back into WordPress.
