Boris won the Russian qualifier for the 2017 World Championship, but lost 2–1 to Dragutin Horvat in the preliminary round. Kolstov entered Q School in a bid to earn a PDC Tour Card and he reached the last four.
Koltsov and Aleksandr Oreshkin met Australia in the second round of the World Cup after seeing off Hong Kong 5–3 in the first round; Oreshkin beat Kyle Anderson 4–2, but Koltsov failed to win against Simon Whitlock meaning a doubles match was required to settle the tie. Russia easily won 4–0 to make it through to the quarter-finals for the first time, where they could only pick up one leg in their singles defeats to the Welsh pair of Gerwyn Price and Mark Webster.
Boris has recently qualified again for the upcoming 2019 PDC World Darts Championship.