You should have paid the first year maintenance fee that would have given you (any MR updates to v2015) and an upgrade to SketchUp 2016.
Then if you have paid the intervening maintenance fee, you would also get an upgrade to v 2017. (If you let your maintenance contract lapse, you may have to pay a late fee.)
You should most definitely contact Support, and get the upgrade license for 2016 if you will continue running on Windows 10. (Each version uses a different license.) Once you install a newer version on that machine, you cannot move the old license to another machine.
Read carefully the entire chapter on licenses in the User Guide:
SketchUp 2016 on Windows now has the dockable / autohide trays for the inspector panels (like LayOut has.)
See what else is new at the Release Notes: https://help.sketchup.com/en/article/141303