Users of Sumatra PDF have a new version available for download. It is a minor release that incorporates only a small set of repairs.
The changes present in Sumatra PDF 2.2.1 eliminate the problem with failure to remember the viewing position in the case of ebooks.
In many cases, opening files from a network drive would cause the application to fail to close properly. The developer managed to mend the issue in this revision.
This was not the only stability problem eliminated by the developer as the current release also features fixes for most frequent crashes and PDF parsing robustness.
The previous update for the application focused on extending the support for ebook file types and added support for documents encrypted with Acrobat X.
Sumatra PDF is also available as a portable download and can be obtained from here.