nothing changed Jan 1 2024 other than a loophole regarding remitances was closed. The current administration is considering reopening it, if they survive long enough. I can find no evidence that the requirement to register has ever been enforced against expat retirees. Their pensions are not taxable, and the tax office do not seem to want the hassle.
When l used the monthly income method, l was always required to show the source of my money in the UK. I used to attach my yearly P60, and that was sufficient for Korat immigration.
Must be very new. Renewed my visa less than two weeks ago without any problem although the local immigration wanted to see a statement for 3 months before the date of renewal. Question is, will they do 4 months on the spot, or will the statement have to be ordered? That can take 10 days.