Russian forces have widely utilized antipersonnel mines since their full invasion of Ukraine commenced on February 24, 2022.
The Monitor also reports the use of antipersonnel mines by Ukrainian government forces in and around the city of Izium in 2022 when the city was under Russian control. Ukraine is bound by the Mine Ban Treaty.
src (2014)
They say it’s a matter of necessity. And it seems withdrawal from the treaty is an option.
/edit: Another source from Wikipedia:
They’ve already been using them.