This latest Apktool supports android marshmallow 6.0 API 23 and it also includes updated v2.0.8 of the smali / baksmali project.It is a tool for re engineering 3rd party, closed, binary Android apps and Games.You can download the latest version of Apktool.jar with marshmallow support from below link.Thanks to Connor Tumbleson aka XDA Senior Member iBotPeaches
It can decode resources to nearly original form and rebuild them after
making some modifications.It makes possible to debug smali code step by
step. Also it makes working with app easier because of project-like
files structure and automation of some repetitive tasks like building
It is NOT intended for piracy and other non-legal uses.Just try to be fair with authors of an app,
that you use and probably like.