There are only a few fixes in the update but the most important is the fix for the crash on load when restoring a game that was the black screen bug from 1.0.1.

Here are the changes for 1.1.5:
+ Fixed save games with black screen bug turns into crash on load
+ Added a way to reset current game in Setting app
+ Red and blue pages automatically start book movies
+ Fixed crash when accessing forum or support with in-game browser
+ Fixed hour tens digit wrong in planetarium control panel in OS 3.0

The "reset current game" setting is not in the option screen within Myst. It is in the Settings app which should be in the first page of all your apps, the one with gears for an icon. Look in the lower section of setting (where all the apps stick their settings) and look for Myst. Selecting Myst you will see the "Rest Current Game" settings which defaults to OFF. Turn this setting to ON to reset the current game. You should only need to do this if for some reason the current game causes a crash when Myst is loaded, making it impossible to get into the game. After Myst is loaded, this setting will be reset to OFF.