Normally, SketchUp only checks for more recent updates to the version you are using. Sometimes though it seems to pick up on the next major release update.
Check the Help menu, About SketchUp, and see if it says 17.2.2555. If it does, then that is the latest Windows version.
actually it has the same serial no besides the first letter denoting the concerning version:
SketchUp Pro 2022 : Serial No. βXβ¦β
SketchUp Pro 2021 : Serial No. βWβ¦β
SketchUp Pro 2020 : Serial No. βVβ¦β
SketchUp Pro 2019 : Serial No. βUβ¦β
SketchUp Pro 2018 : Serial No. βTβ¦β
SketchUp Pro 2017 : Serial No. βSβ¦β
SketchUp Pro 2016 : Serial No. βRβ¦β
SketchUp Pro 2015 : Serial No. βQβ¦β
SketchUp Pro 2014 : Serial No. βPβ¦β
SketchUp Pro 2013 : Serial No. βNβ¦β
SketchUp Pro 8 : Serial No. βMβ¦β
SketchUp Pro 7 : Serial No. βLβ¦β
SketchUp Pro 6 : Serial No. βKβ¦β
SketchUp Pro 5 : Serial No. βJβ¦β
SketchUp Pro 4 : Serial No. βIβ¦β
SketchUp Pro 3 : Serial No. βGβ¦β
SketchUp Pro 2 : Serial No. βFβ¦β