A number of people who have tested the 5.0.1 beta update, released by Apple earlier this week, said that they have noticed improved battery life after they installed the update. The software is presently only available to registered developers for the iPhone, but Apple has said that it will make a version publicly available "in the next few weeks". The update will be available "over the air", so that it will not require a computer for installation.

One developer said that the "Setting Time Zone" preference had been fixed: "In the [iOS 5.0] betas and in the first release, turning it on would instantly bring up a purple arrow [in the phone's menu bar], indicating it was using your location - and this would stay on permanently. It really drained the battery." The "Setting Time Zone" preference was automatically set on in iOS 5.

Another location service, for Traffic, has also been tweaked: "on the release version, if you turned on the location service for traffic, then went into Maps, looked at traffic, and then quit Maps, again the purple arrow would stay in the status bar. This is no longer the case – Maps stops using your location when you close it."

The use of the location services system – which tries to poll nearby mobile phone masts, Wi-Fi networks and even the GPS location chip in the phone – can drain the battery rapidly because they become an always-on system which is constantly trying to check for any change in signal strength from the sources which would indicate movement. GPS in particular requires lots of processing power because GPS signals are below the level of thermal noise in most environments and require special amplification systems to determine the signal.

Last week location services were suspected of being behind the rapid battery drain experienced by some users.

"Without this fix the battery was lasting about four hours," said another developer who applied it to their iPhone 4S. "It's now up to the Apple stated times, around the same as the iPhone 4 … The battery life of iOS 5 has been strongly criticised and this issue now appears to be resolved." Apple has said that the iPhone 4S would have a standby time while connected to a Wi-Fi network of about 200 hours. The iPhone 4 and iPhone 3GS, which can also run iOS 5, have stated standby times of 300 hours. Apple has not provided any explanation for the difference.

Another one said: "It's only been a day but (anecdotally at least) things seem to have improved."

Siri, the built-in voice recognition system on the iPhone 4S, also now works better with Australian and Scottish accents, which had proved problematic for the initial version. However, one developer noted that iOS 5.0.1 has not fixed the "Siri volume bug", which they described thus: "After using Siri, if you lock your phone you'll hear that the phone's volume has been set to full (you'll hear the locking/unlocking sound really loud). Tapping volume up or down fixes it, and it returns to normal after 15 seconds: it seem Siri needs to boost the volume. This bug *hasn't* been addressed in 5.0.1." It is not known whether Apple plans to address this.

The 5.0.1 update also includes better support for synchronising documents between services such as Instapaper.