If auto upgrade is currently enabled for your version of AAD Connect, don't be too surprised if your version auto upgrades to this version before it becomes publicly available. Microsoft sometimes trial updates some customers ahead of the public release.
Azure AD Connect version 1.1.558.0 continues to fix issues with OU filtering and expands the number of configurations where auto upgrade can be enabled. It's important to note that if your configuration falls under the new configuration requirements, upgrading to this version will enable auto upgrade. If you don't want auto upgrade enabled, you should run the following cmdlet to disable it:
Set-ADSyncAutoUpgrade -AutoUpgradeState disabled
You can always download the latest public release of AAD Connect here.