This month, the IRS released the first W-2C update since 2014. Aside from Copy A, W-2C is now fillable. There were several changes to the Copy D Employer Instructions. Employers are cautioned against sending IRS.gov printed forms to the SSA. A reference to the old 250 form electronic filing threshold was removed and replaced by a note to check the instructions to determine whether electronic filing is required. There were also unimpactful changes to language and formatting, and the revision date has been updated throughout.
The revised W-2C can be found here.