ringtone disabled in bedside mode). It criticizes the limited customization options compared to BlackBerry OS (Alert tone volumes, alert light colour). Regarding the apps in BlackBerry World "really impressed by the quality of apps BlackBerry World has to offer", it notes that the application ecosystem is not as large as Android and iOS because of its age (brand new) and finishes with "doubtlessly many more will come around once they see the Z10 getting traction in the wild." Its general summary of BlackBerry 10 (with thought for its predecessor) "is that BlackBerry 10 really is the best of the old and the best of the new assembled seamlessly into an elegant, practical, and integrated package." As of Q2 2013, the new BlackBerry 10 platform had almost the same number of developers using the platform as the legacy BlackBerry 5/6/7 had just before the release of BlackBerry 10. Within a few months from its launch, the BlackBerry 10 platform was used by approximately 15% of mobile developers. BlackBerry 10 added a compatibility layer for Android software, which allowed developers to repackage their Android apps for distribution on BlackBerry World. This advertised feature has received a poor reception as the Android apps "performed abysmally on the phone. Sluggish, ugly, and disconnected from the core OS. In fact, because these apps are being run in a software emulation of Android — Gingerbread no less (that's version 2.3) — they bear little to no relationship to the rest of the operating system". Later versions added the ability for users to manually install Android app packages. Beginning with the BlackBerry Passport, Amazon Appstore was bundled with BlackBerry 10 to provide an additional source of third-party Android software. BlackBerry CEO John S. Chen hoped that Amazon's own smartphone, the Fire Phone, would bolster the adoption of the Amazon store and attract more major developers to it, and in turn, BlackBerry's ecosystem. The Fire Phone was a commercial failure, however, which led to BlackBerry's decision to develop an Android phone of its own, resulting in the BlackBerry Priv. Version history BlackBerry BBX During the BlackBerry DevCon Americas Conference in San Francisco held from October 18–20, 2011 RIM announced the future platform for devices as "BlackBerry BBX", a development fork of the QNX Neutrino RTOS version 6.5.0 platform. On May 1, 2012 it was announced at BlackBerry World 2012 held in Orlando that it would be instead be