The issue was found to affect the iPhone 4S, an older model of the iPhone. Some who had upgraded to 6.1, released a few weeks ago, reported having problems, including degraded 3G connectivity or trouble making phone calls or connecting to the internet at all. Other users reported problems with Microsoft Exchange after the update, and AOL said 6.1 interfered with its mobile meeting software for iOS.

Last week Austria’s 3 and Germany’s Vodafone warned their subscribers not to upgrade to iOS version 6.1 until Apple had a chance to address the issues. The update issued Monday is supposed to have addressed all of them.

Related research and analysis from GigaOM Pro:
Subscriber content. Sign up for a free trial.

• Analyzing the wearable computing market
• Takeaways from mobile’s second quarter
• Confused about the wireless markets? Here’s a breakdown