IBM no longer sells or supports OS/2. Therefore, some older versions (like OS/2 Warp 4.0) exist on abandonware sites. While this is legally gray, IBM has not been known to enforce copyright on these legacy ISOs. You can find OS/2 Warp 4.0 ISO files for free online. These will not run on modern hardware, lack UEFI support, and cannot use NVMe drives. You would need to run them on a vintage PC or in an emulator like PCem or 86Box.
Historically, there were promotional giveaways of the "Blue Lion" edition via OS/2 user groups (such as VOICE). As of late 2023, this is largely discontinued, but it is worth checking the official ArcaOS forums or Reddit’s r/OS2 for occasional community keys. Be wary of any site claiming "cracked" versions. arcaos download iso free
If you are a hobbyist or a business needing to maintain legacy software, here is the proper path to acquiring the OS: 1. Purchase a License IBM no longer sells or supports OS/2