Hi Rg,
The MeoStar B1 was the first line of roof prism binoculars from Meopta, starting in 2005.
Since then, the regular (non-HD) offerings have been 8x32, 10x32, 7x42, 8x42, 10x42, 7x50, 10x50, 12x50 and 8x56.
The first HD model was the 10x42 in 2012, with the 12x50 and 15x56 following (there’s not been a non-HD 15x56).
And as you indicate the binoculars are marked to indicate the presence of one HD lens in each objective.
The B1.1 upgrade was introduced in 2019, with the diopter knob including a click lock.
See:
A Brief Introduction to the New MeoStar B1.1 Binoculars
The B1 Plus upgrade dates from 2020, with a new RA covering and some colour options.
For a lot more detail about the B1 series, see:
New MeoStar B1 Plus Binoculars
John