In order to allow players that won ranks in crates to upgrade them on the store, we have changed certain server's rank upgrades to instead be rank upgrade vouchers. What this means is that instead of receiving the rank directly you can buy a voucher (piece of paper) that when right-clicked will give you the rankup.
Please keep in mind that you must have the required rank for it to work, otherwise it is just a piece of paper you can't use. The required rank is the rank before the arrow for example in "rank1 -> rank2 rank upgrade", rank1 is the required rank and rank2 is the rank you get after redeeming the voucher.
Please note that once you receive the voucher it is your responsibility to not lose it, if you lose it you will not get another one.