They are still allowed. This guy's had one for 30 years. They have always been a real pain in the you know what. In the past the, 2017 and prior, the Form 1040 had a place at the top to insert the fiscal year end. Not any more. IRS 1040 instruction say to type that info at the top of the new 1040 or 1040-SR. Thanks for the input.
I have only one as well. In previous years, I "override" the dates at the top of the form. This year since it has to be paper filed and that option was not available, I printed and wrote in red sharpie "fiscal year taxpayer and the dates". Unfortunately they receive notice every year on their payments and must call the IRS every year to "remind" them they are fiscal year taxpayers so I also recommend getting a POA in conjunction with filing as you will most likely need it and possibly adjust your fees accordingly.