Some times people report issues on Github which get fixed on Github, but are not yet part of an official release of Time Manager. In order to get the most recent master you need to go to the QGIS plugin directory on your computer:
~/.qgis2/python/plugins # for Linux and Mac
C:\Users\{username}\.qgis2\plugins\python # for Windows
You need to delete the directory "TimeManager" from there and then and run, from this directory:
git clone https://github.com/anitagraser/TimeManager.git
This will replace the current version of the plugin downloaded from the QGIS plugins repository with the current version from github. For this, you need to have Git installed.
If you want to update the plugin again, go to the QGIS plugin directory, go into the TimeManager directory and type:
git pull