Yes, there are versioned API's and types in the DocumentFormat.OpenXml library pertaining to Office 2007, 2010, 2013, 2016 and 2019 (currently). Since this question is about the 2.8.1 version (currently the open source version of this is at 2.13.1, working towards 2.14), you should really direct your questions about the project to:
In general, you can ask "how to" questions by following the guidance on the readme for the github repo which says:
If you have "how-to" questions please post to one of the following resources:
Microsoft Q&A Forums (tag: office-addins-dev)
Stack Overflow (tags: openxml or openxml-sdk)
For this forum, since this tag doesn't scope to the Open XML SDK, I'll change the tag from [openspecs-questions] to [office-addins-dev], however, that forum mainly targets the 2.5 version of the SDK.
I hope this helps.
Sr Escalation Engineer
Microsoft Open Specifications