Hi @matan alter ,
1) is it possible to keep the data from the scom 2012 and import him to the 2019 version ?
I'm afraid this is not possible when doing a side-by-side upgrade, you are basically installing a whole new SCOM environment with new databases, so you are actually starting from scratch.
2) in my 2019 Group , does the agents can work in version of 2016 ?
i means that i will install the 2016 agent and they will reportes to my 2019 MG.
Yes, the SCOM 2019 agents will work just fine with 2016, and the 2016 agents will also work fine with SCOM 2019.
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Best regards,
Leon