If you compare the changelogs for iText 5.5.6 with previous change log entries (for instance the one for iText 5.5.5), you immediately notice that we're using a completely different style. We have successfully moved from svn on SourceForge as our main code repository to git on a private GitLab server. From out GitLab server, the source code is now distributed to SourceForge (search for the git repository, the svn repository is no longer updated) and GitHub. Changelogs are now mostly generated automatically based on the GitHub logs.
This move immediately triggered some pull requests with code contributions from developers like you. One of these contributions made it into the final release: PdfGraphics2D now has support for CMYK.
For this release, we have continued working on the CleanUp functionality in the xtra package. We now support redaction that involves lines and shapes. To achieve this, we enhanced the parser package so that it now also produces parsing info about operators such as moveTo, lineTo and stroke. We used a third party clipper library to do geometric calculations.
There were also some improvements with respect to Arabic text. We are looking at fonts in general, and we are making good progress, but please don't expect the results in the next couple of releases. Better font support requires a lot of changes at the lowest level of iText and we won't release new font functionality before 2016.
As always, we've added plenty of improvements and applied several bug fixes based on feedback from our paying customers and based on feedback from users on StackOverflow. Note that the changelogs contain links to JIRA: that's our closed ticketing system. Only paying customers have access to this issue tracker, but most of the tickets are only visible to core iText developers.
There was a mistake in the metadata of iText PDF/A 5.5.6: the Maven POM file still listed iText 5.5.6-SNAPSHOT as a dependency. We have fixed this in iText PDF/A 5.5.6-1. This is only relevant if:
You build iText PDF/A from source.
You use Maven's dependency mechanism in your project. In this case set the dependency of your project on itext-pdfa 5.5.6-1 instead of 5.5.6.
Functionally, versions 5.5.6 and 5.5.6-1 are equivalent. So if you have already deployed 5.5.6, there's no need to replace it with 5.5.6-1.