Development:Adding activity locks
Overview of Activity Locking
Activity Locking is a type of conditional activity in Moodle. It is not part of the standard Moodle and requires a special installation.
What does it look like
This will show a few screen shots of a course(s) that uses lessons.
In the edit lesson setting the teacher will see 
The general tab is the standard lesson setting found in 1.6. Those have not changed.
The Activity Lock tab looks like this. We are in the second lesson and need to determine what are the requirements for entering this lesson. 
The setting tab has: 
These are visibility settings. Notice help buttons.
The student view of two lessons, where the future lessons are not hidden. Shows second lesson is locked.
See Also
There is a very specialized-limited type of activity locking under a lesson (activity) setting called dependency in 1.6. See: *https://docs.moodle.org/en/Adding/editing_a_lesson#Dependent_on .
