The latest version available is MuPDF 1.9, which has been recently released, coming with changes.
New command line tools: create and run.
New low-level Java interface for desktop and android.
Bidirectional layout for Arabic and Hebrew scripts.
Shaping complex scripts for EPUB text layout.
Noto fallback fonts for EPUB layout.
Create new PDF files from scratch.
Read an annotated content stream in a text file and write a PDF file, automatically embedding font and image resources.
The interface is similar to the new Java interface.
Optional multi-threaded operation (Windows and pthreads).
Optional low memory mode (primarily for testing).
In order to successfully install MuPDF on your Ubuntu system, you need to do is add the PPA to your system, update the local repository index and install the MuPDF package:
Open terminal and insert command line...
|$ sudo add-apt-repository ppa:ubuntuhandbook1/apps
$ sudo apt-get update
$ sudo apt-get install mupdf mupdf-tools
Optional, to remove mupdf, do:
|$ sudo apt-get remove mupdf mupdf-tools|