When working across many different Exchange environments it is useful to quickly know which build version you are on for each Service Pack, Cumulative Update or Update Rollup of the specific Exchange release.
The commands below provide a quick reference to obtaining the builds using the Exchange Management Shell.
Run the relevant command in the Exchange Management Shell depending on your Exchange version to find out which build number you are running then using the link at the bottom see how up to date your environment is.
Exchange Server 2019
Get-ExchangeServer | Format-List Name,Edition,AdminDisplayVersion
Exchange Server 2016
Get-ExchangeServer | Format-List Name,Edition,AdminDisplayVersion
Exchange Server 2013
Get-ExchangeServer | Format-List Name,Edition,AdminDisplayVersion
Exchange Server 2010
Get-Command ExSetup | ForEach {$_.FileVersionInfo}
Exchange Server 2007
Get-Command ExSetup | ForEach {$_.FileVersionInfo}
For a full list of Exchange build number and release dates see the official Microsoft documentation at;
https://docs.microsoft.com/en-us/exchange/new-features/build-numbers-and-release-dates