decommision resource domain and install Exchange 2016 in Account domain

[Deleted]

Following situation at a customer:

- Account and Resource forest

- Office 365 tenant

- Azure AD Connect  machine running in Account forest, syncing both directories

- ADFS in Account forest

- Exchange 2010 in Resource forest with Hybrid setup

What we want:

- decommision resource forest/domain and Exhange 2010

- install Exchange 2016 in account forest

- make 2016 the hybrid

I was wondering which steps we had to take. We are now already migrating user to Exchange Online. For a new user we create a user with Linked Mailbox in Resource domain. We ADMT it to the Account forest, we trigger ADSync. A mailuser is made in Office 365 and we iniate a mailbox move.

Then in the resource forest we have a Mail Contact in Ex2010 and a disabled account in AD.

1- How can we get rid off these migrated users?

2- When can we install 2016 in the account forest, can it do any harm when we install it next to Ex 2010 which is in the other forest(ofcourse we have  a trust)

3- How to move on from here?

Thanks for your support!

[#2]

Does https://practical365.com/exchange-server/removing-premises-exchange-servers-migrating-office-365/ help?

[#3]

Thanks! I also apologise, since I have also started the same topic in the Exchange community since I thought this community was more appropiate. And where I also got some good recommendations. https://techcommunity.microsoft.com/t5/Exchange/decommision-resource-forest-and-install-Exchange-201...