I really like to go snowshoeing during the winter. I'm going up to 3500 meters and when I'm doing long tours I would really enjoy to try out winter camping in very remote areas. Is it a good idea to buy/rent a special tent for that purpose? Or can I just use my current tent? What features should I look for if I choose a tent for winter camping?
The primary difference is good winter camping tents are designed to stand up to and / or mitigate snow building up on top of them. Ventilation is also very important as you don't want moisture from your breathing to build up in the tent as you could wake up with your clothes wet.
Winter tents will often have larger vestibules, as you will typically have more gear for winter camping than three season camping and you don't want all your gear covered with snow.
A lot of winter tents will also be shorter than their three season counterparts. This is due to a lot of winter camping being done on mountains with higher winds which a lower profile helps to mitigate.
If you use your current tent, you should make sure the rain fly (outer layer) covers the entire tent. Otherwise you will have a healthy layer of frost on the inside of the tent (in the uncovered area) every morning.
Four season tents usually have more poles and are sturdier than three season tents, for wind and snow protection. They may also have the option of closing off the ventilation for warmth.