compatibility issues b/w logic pro x and Logic Pro 11 projects

You need to learn exporting your tracks. You cannot assume that all users have the same Logic version, the same software in general, the same plug-ins, the same operating system.

File > Export > x Tracks as Audio Files

It is not a question of whether you compress or not. But there is a crucial difference between a Logic project and exported tracks/files. If you send a Logic project, you would have to assume that the other person has exactly the same set-up as you, but this is very unlikely. The usual professional standard procedure is to export (bounce or render) your session as separate tracks that contain all the sound(s) generated or transformed by the plugins and also have the same starting point. The other person must be able to import the files, regardless of which software or setup he/she is using.

The most convenient way is to learn and use the option File > Export > x Tracks as Audio Files.