Thank you for contacting Telerik Support.
We have arranged the latest OpenAccess version to be distributed with each new Sitefinity release, so if you're using the latest version of OA there should be no problems with assembly version mismatch,.
However, if you need to integrate this functionality in an older Sitefinity distribution, and are running the latest OA SDK, for example, you might indeed experience some issues like the ones mentioned in your opening email.
For this particular scenario I believe you might find Josh's blog post
on the topic useful, hope that helps.
Please do not hesitate to let us know if any issues persist, I'll be glad to assist you further.
All the best,
the Telerik team
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