08 may 2016 Release
Ubooquity 1.10.0 is available.
Update: 1.10.0 has been replaced by 1.10.1 which contains a fix for reading secured PDF documents and prevents the usage of Java new color management library (LittleCMS) which is apparently absent from some systems.
Starting with this version, Ubooquity requires Java 8.
(Java 7 support by Oracle stopped more than a year ago, time to upgrade !)
Fixed PDF rendering problem caused by some versions of Java (cf forum)
Fixed user authentication not working when shared folders are symbolic links (cf forum)
Apparently, the old library used by Ubooquity for PDF rendering has been broken by recent updates of Java (both 7 and 8). This library has been removed and all PDF (books and comics) are now renderend by an updated version of PDFBox, which happened to improve a lot recently.
Among the consequences is a probable performance hit (CPU and memory) for some people as JPedal (the old library) was faster than PDFBox. On the other hand, almost all properly formed PDF can now be read online provided your device is powerful enough.
About symbolic links
If activating user login prevented you from seeing your shared folders content (as described on the forum), you might have shared (knowingly or not) a symbolic link instead of an actual directory.
Ubooquity now supports symbolic links: to fix the issue, just edit and save your books/comics settings again.
Get it on the download page