To lock employee availability you will need to navigate the Employee Availabilities menu under the Scheduling tab. Each employee profile has its own availability lock date. Availability lock dates can be changed by any user with Scheduling Modify access. Any user with Scheduling Modify access can add/edit/delete availabilities for any other user regardless of the lock date. Users with Scheduling View access can only add/edit/delete availabilities after the lock date. For example, if an employee's lock date is set to Jun 30, they cannot edit any availability on their calendar before Jun 30, but they can edit anything after Jun 30.
You can edit the lock date for each employee individually or you can set the lock date in globally for all employees (or do so by location using the filter) by using the LOCK AVAILABILITY button at the top of the Employee Availability page. This will update the lock dates for all users visible on the page based on your current filter (All Locations or one primary location selected).
To change the lock date for one employee only, you can click on the little padlock next to any employee name to change the lock date for that employee's availability:
As of June 26, 2023, there is no more "lock/unlock" option for employee availabilities. As of the release, the new feature locked availabilities by date, setting the locked employees to a lock date of 12/31/2023. Any unlocked employees at the time of this release found their lock date set to June 26, 2023. This was done in an effort to make the migration process for all users as seamless as possible.
Users with Scheduling Modify access should monitor and update the employee lock dates to follow their scheduling process. For instance, if managers typically "close" accepting availabilities after the schedule is published for the next two weeks, the availability lock date should be set for all employees after the next two weeks until the next schedule is published.