Originally Posted by rickair7777

It has absolutely nothing to do with currency at all.

There are two types of ATP written:

Not Expired: Can be used for the checkride under any circumstances.

Expired: Can only be used at a 121 / 135 operation (or military transport equivalent)

You don't have to be current, stay current, be continuously employed, stay at the airline where you took the test, or any of the other old wives tales.

An airline may require a current atp written to get hired, but that's not regulatory.