The Coinbase iOS app, which enabled users to buy, sell and send bitcoin, has been removed from the Apple App Store less than a month after its launch.
It appears it was Apple's decision to remove the app, as Coinbase engineer Craig Hammell revealed on Hacker News that his company was not responsible for taking it down.
Another forum member suggested the app was removed for "quality reasons", but Hammell responded by stating: "That wasn't the reason that Apple provided us with."
The iOS app, which was released on 22nd October, enabled users to see how many bitcoins they have in their wallets, plus view any recent transactions.
"We're not sure why it was taken down and we've reached out to Apple to request clarification," Brian Armstrong, Coinbase CEO and co-founder told TechCrunch.
At the time of release, Coinbase co-founder Fred Ehrsam said: "This was one more step in our mission to make bitcoin easier to use. Now that I have the iOS app, I use it to pay back my friends when I'm out and about since it's so much easier than other ways to do it."
Android users can still download the app from the Google Play Store, free of charge.
Other bitcoin wallet apps have also experienced problems with the App Store in the past, including the BitPak and Blockchain.info applications.
Back in early May, the app's designer, Rob Sama, received a notification from Apple stating that the application had been deleted. A post by Sama on the BitPak site states: "I had not been given any reason why, just a simple electronic notification that it had been done."
He then received a call from Apple around a week later and was told the app had been removed because "that bitcoin thing is not legal in all jurisdictions for which BitPak is for sale".
Sama asked which jurisdictions bitcoin was deemed to be illegal in, and was told: "That is up to you to figure out."
The developer decided to give up working on BitPak and focus on other projects, although he remains passionate that bitcoin wallet apps should be permitted.
"I still believe that the most logical place for a bitcoin wallet to reside is on the mobile phone. It is extremely unfortunate that Apple has chosen to take this stand. I know that there are people working on dedicated dongles to overcome this issue. And maybe that is the way this will play out," Sama added.
Rated four out of five stars, the app enables users to send and receive bitcoin payments, view their wallet balances and scan paper wallets.
The first version of the app went live in early April 2012, but Apple removed it the following month with no explanation. Blockchain.info enquired why the app had been removed and Apple replied that it violated App Store View Guideline 22.1, which states:
"Apps must comply with all legal requirements in any location where they are made available to users. It is the developer's obligation to understand and conform to all local laws."
A version of the app, which had limited functionality, was then released on 13th April 2012, with full wallet functionality then reinstated three months later on 11th July.
A representative of Blockchain.info said his company is following the recent development surrounding the Coinbase app "very carefully".
"We won't speculate as to why Apple has removed the Coinbase app but we're hopeful it has nothing to do with bitcoin and that they come back soon," he added.
The representative went on to say that, in the meantime, Blockchain.info "continues to have an iPhone app loved by users and praised by geeks".
Australia-based company CoinJar created a bitcoin wallet app, which was approved by Apple in October this year.
It hails the app as having:
"... an easy-to-use interface, a super-responsive QR scanner and all the features you need to send and receive payments.
Your wallet is in the cloud, wherever you are. There's no blockchain to download and everything just works out of the box."
Other bitcoin apps
There are a number of other applications on the app store that bitcoiners may find useful, but they don't offer wallet functionality.
Apps such as ZeroBlock and btcReport operate as bitcoin price tickers and other applications such as Bitcoin Monitor offer more in-depth information, such as mining difficulty, total number of bitcoins in circulation and the average time it takes for a new block to be mined.
CoinDesk is awaiting comment from Coinbase.