For iOS 9, Apple is reportedly bulking up the features of its virtual personal assistant Siri.

According to sources, an update for Apple's latest OS version will allow Siri to transcribe voicemail messages as well as answer calls for users.

The Business Insider reported that employees of the Cupertino-based tech giant are using and testing the virtual assistant's newest services. However, these may not debut with the launch of iOS 9 in September. Instead, the company may unveil Siri's new features through an update sometime next year.

As described by the tech site's sources, Apple's upcoming service will make Siri functions more personal and intuitive.

Before the development of the services, recipients of voicemails had to listen to the verbal messages left by their contacts.

But with the service, Siri will be able to transcribe the verbal messages, allowing users to read through them as text files.

As noted by Mac World, Siri's transcription capability will not be debuted as a pioneering service in the tech industry. Apple's major rival Google has already released a similar feature to users dubbed as Google Voice.

However, when it was first debuted, Google Voice was criticized by users due to its transcription errors. But in July, Google announced that it has managed to reduce the mistakes of its service by 50 percent.

Aside from the transcription feature, Apple will also allow Siri to answer calls for users through the iCloud Voicemail.

When the users are unable to answer a call, Siri will be activated. It will then tell the other person on the line that the device's owner is unavailable. It can also be programmed to inform the caller the location of the user or why he or she isn't available to take the call.

The callers can then leave a voicemail which Siri will transcribe for the device's owner.

An upgraded Siri is only one of the features that Apple will launch with its upcoming iOS 9 platform. Some of the enhancements that users can expect to see include the Picture in Picture, which will allow iPad users to multitask by opening two apps at once.

The new OS also comes with various firmware improvements that can prolong the battery life of devices as well as a renamed payment service dubbed as Wallet. For the iOS 9, the Wallet will provide a wide range of support for store gift cards, loyalty cards, and debit and credit cards.

Apple officially introduced the iOS 9 during the recent Worldwide Developers Conference in June.