Hello Hugo,
1- Do i need to install the Dynamics 365 Server Service Pack 1, version 9.1 first? Or can i go for the latest version?
As v9.1 cumulative updates are FULL, you don't need to install v9.1 RTM rtm first. You can install directly v9.1.17.
2- Is a in-place upgrade safe to do? (After all backups created)
In general we prefer separate environment installations because:
- Some customers have played around with CRM files on 9.0 that will cause problems on overwriting those files on installing v9.1. So the installation may be inconsistent and cause problems to upgrading DBs.
- In place upgrades will automatically try to upgrade the Database, so if something fails, that organization may not be available anymore until you fix the upgrade error.
Please check this article to disable automatic updates first, if you use an inplace upgrade.
On in place upgrades, imagine your deployment has 100 orgs, the process will only finish once all 100orgs that are enabled are attempted to be upgraded. As this causes sometimes a customer to NOT notice that a DB had a failure and will continue to use it, although becomes on a corrupted state.
learn.microsoft.com/.../update-to-v91
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By default, when you apply the Dynamics 365 Server, version 9.1 update, all organization databases that are enabled in the deployment will be updated to Dynamics 365 Customer Engagement (on-premises), version 9.1. Administrators can control which organization databases are upgraded in either of the following ways:
Disable the organizations you don't want upgraded. Notice that all organizations must remain disabled until all the servers in a multi-server deployment are updated. More information: Deployment Manager: Disable or enable an organization and PowerShell: Disable-CrmOrganization.
Configure the AutomaticallyInstallDatabaseUpdates deployment setting to false.
Add-PSSnapin Microsoft.Crm.PowerShell set-crmadvancedsetting -configurationentityname Deployment -setting AutomaticallyInstallDatabaseUpdates -value $false
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Separate environment with Handy DB restores if the update fails are easier to handle.
3-before installing the SP1, do i need to install the latest 9.0x version?
No.
We have seen rare scenarios where a DB may give an error if updated from 9.0.10 to v9.1.17, but not if 9.0.10 -> 9.0.46 -> 9.1.17.
But this is about DB update and you are focusing on Server install.