Adding to the chaos, DC Cycle 4 technically has started already but the IRS is not yet open for business to receive submissions. The IRS expected to open the submission window from Feb. 1, 2024, through Jan. 31, 2025, but I have not seen an announcement.
If the window is open soon, we likely will be doing Cycle 4 amendments for everyone with the restatement period running from the latter part of 2026 into 2028.
The December 31, 2026 hits right around the beginning of that restatement period.
The LRMs were updated this January and are available here https://www.irs.gov/pub/irs-tege/dc-lrm0124.pdf if anyone has time to spare to read through 149 pages.
If the submission window does open soon, imagine how much guidance has yet to be issued that will not be in the LRMs included in the Cycle 4 documents.