iOS 5 Gold Master, GM for short, is the final version of the operating system that Apple releases first only for iOS application developers, giving them the opportunity to test it and report any problems encountered. This version of an operating system is generally released to developers about 2-3 weeks before the release from iTunes and usually the GM version is published without changes as the final version of an operating system. In general, in the case of major versions of iOS, Apple releases a GM version during the presentation conference of some products and new functions implemented in the operating system.
Year iOS 5 GM should be released next week, according to some information received from Apple's partners, but if this is true then next week we should also see the iPhone 5 presentation conference. These GM versions contain all the innovations implemented by Apple for users, more than the available available in beta versions and theoretically they remain unchanged during the entire period of availability for developers. Last year, iOS 4.2 was available in the GM version for a few weeks and just a few days before the launch, Apple made some substantial changes by releasing a changed version that upset the plans of the Dev Team who failed to make a untethered jailbreak solution for several months.
iOS 5 GM will NOT be jailbroken or decoded with new programs because the Dev Team is waiting for the final release, so don't get your hopes up that you will be able to install the GM version and decode an iPhone with non-decodeable baseband. iOS 5 GM will be able to be jailbroken on all current devices, except iPad 2, but it will be a tethered jailbreak. iOS 5 GM is just the preamble to the release of iOS 5 and as soon as it appears we will know absolutely everything that Apple has prepared for its users.
Having said that, you now know what a GM version of an operating system means.
