. Keys found on third-party sites for this version are often: Temporary: Beta keys that may have already expired. Volume License Keys (KMS):
Since Mondo was a pre-release version, there are from Microsoft . Any website claiming to sell "Mondo 2016 keys" is likely selling unauthorized or expired licenses. microsoft office mondo 2016 product key
Official support for the retail version of . This means Microsoft no longer provides security updates or technical support for any 2016 variants, including Mondo. Microsoft Office Mondo? - Microsoft Q&A microsoft office mondo 2016 product key
Activate Office 2016 (legitimately):