We recently announced the availability of a new SharePoint CSOM version targeted for SharePoint Online.
This update contains new Project Online CSOM capabilities and also few updates on the existing SharePoint CSOM assemblies. You can find the latest CSOM package for SharePoint online, including now the Project Online CSOM assembly, from the NuGet gallery with an id of 'Microsoft.SharePointOnline.CSOM'. We are also working on updating the redistributable package in upcoming weeks, but you can already right now start using some of these new capabilities in your solutions.
Version of the released CSOM package is 16.1.4915.1200. Old version of the NuGet has not been removed, so that your existing solutions will continue working without issues and you can decide when the new version is taken into use. Notice that even though the Nuget version is increased to 16.1.4915.1200, actual assembly version of the released assemblies is 18.104.22.168. You can also check the version of the assemblies from the File Version attribute, which alings with the Nuget version.
You can find all the details in the following blog post: