Hi Massoud,
We've had to adjust our plan a bit about SP5, in light of Covid and related staffing issues . . . . The *new* plan for SP5 is to first make it compatible with PHP 7.x, which looks like it won't be as tricky as we feared. Then we are going to focus on two areas: on the front end, we plan to a) get all data from the API so there aren't live calls to the database, and b) rewrite the front end for better theming and customization. On the back end, we are going to focus on the guides module, in order to a) simplify the UI a bit, b) refactor the JavaScript to squash bugs and speed things up.
As for timing . . . again, we're short-staffed. The initial commit, making it PHP7-friendly, should come next month; the rest will take a little longer.
Not a very specific answer, but all I can offer right now.
Andrew