These licenses are not available anymore if you have this kind of license it will work but to upgrade it - you will have to purchase a new license.Note: current RouterOS version is 5 table modified according to that.

Level 3 can only be obtained in large quantities.Level 2 was a transitional license from old legacy (pre 2.8) license format. The difference between license levels is shown in the table.Level 3 is a wireless station (client) only license. RouterOS licensing scheme is based on SoftwareID number that is bound to storage media (HDD NAND).License Levels You can purchase a Level 3 4 5 and 6. A reboot is required for the key to take effect. You can paste the key anywhere in the terminal or by clicking 'Paste key' in Winbox License menu. The license key is a block of symbols that needs to be copied from your account or from the email you received in and then it can be pasted into the router. PC devices) you need to obtain a license key. RouterBOARD devices come preinstalled with a RouterOS license if you have purchased a RouterBOARD device nothing must be done regarding the license.

Routeros license level