It could have been easily missed indeed, especially during CoViD restriction and focus on other things rather then travel. Also the OP may not have been an active reader of sites/forums like this or HfP as there would have been suggestions on how not to make the other voucher expire (e.g. making a booking to anywhere and then convert it into a FTV).

in any case, I do remember clearly to have received hard copies as well as I decided
to upgrade back to BAPP, but I received my email notification about the BA Blue changes on the 10/06/2021: