The free online training course which will fulfill the §107.65 requirement for recency of aeronautical knowledge (UGR) went online at FAAsafety.gov/ April 6th, 2021. From all indications, the system is fully capable of handling the load, or at least it was in the first few hours when I passed mine.
The course is designated ALC-677. The process will be much like that for Part 61 pilots wishing to add UGR certification. There is an online training course, consisting of a mix of text and video, with quiz questions interspersed, followed by the online test. Passing this new recurrent test allows the operator to conduct flights at night. If you passed the recurrent (UGR) exam PRIOR to April 6, 2021, you will still need Night Operations training and apply for a waiver for your UAG to operate at night.
There is no cost for this online test. Initial Part §107 testing will not be conducted online, and will continue to require in-person testing. However, additional testing services will be available, including Embry-Riddle University.