Apple has released the fourth iOS 7 beta to developers, bringing bug fixes and improvements to the upcoming mobile operating system for iPhone, iPad and iPod touch.

iOS 7 beta 4, which was released on Monday, includes Lock Screen tweaks that see the arrows that previously brought up the quick launch and Notification Center features replaced by straight lines at the top and the bottom of the screen. There is now an arrow pointing right next to the 'slide to unlock' text, too.

See: Apple iOS 7 preview: New features of iOS 7

The Notification Center also has some improvements, including the ability to switch between sections by swiping left and right. There's also a new completed uploads notification.

See also: iOS 7 beta 4 contains key evidence that iPhone 5S will have fingerprint sensor

You can now search Reminders, and the iPhone's search function now has the option to "Cancel."

Other design tweaks include buttons in Safari, the Call, Answer and Decline buttons in the Phone app, slightly new gradients for the Safari and Mail icons, and new AirPlay icons.

iOS 7 beta 4's bug fixes reportedly include a fix for an iCloud syncing issue involving Calendars, and also an issue that prevented high-resolution images from syncing in Contacts.

There are still some glitches in the iOS 7 beta that have yet to be ironed out, including issues with the restoration of voice memos via an iCloud backup.

According to a report from BGR, Apple is expected to release two more betas of iOS 7 before it rolls out the gold master version in early September, which will be followed by the final version in mid-to-late September when the company releases new iPhone models. 

The new beta follows a security attack on Apple's Developer Site that caused the company to take the site offline for more than a week. The key parts of the site are now back up and running.

Apple's previous beta, iOS 7 beta 3, launched earlier this month.

[Via MacRumors]

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