Apple appears to be getting more aggressive in its policing of digital currency apps.

The Cupertino company has moved to restrict at least two separate apps on its online store in recent weeks, a development that has generated speculation in absence of official statements. The issues reportedly stem from a list of cryptocurrencies "approved" by Apple, a policy that dates back to a 2014 update that saw it disclose how it would approve apps that utilize the technology.

Originally seen as a progressive move by the technology firm, the stance has since drawn criticism given recent problems experienced by blockchain startups. These include Jaxx, a digital currency wallet, and ShapeShift, a digital currency exchange, both of which have had to pull iOS apps at the request of Apple.

Last month, Apple was said to have asked Jaxx to remove a specific cryptocurrency, dash (formerly known as darkcoin), because it was not part of a list of so-called "approved currencies" that reportedly includes bitcoin, litecoin and ether.

Jaxx is now set to remove support for dash later this month, and recently disclosed that Apple had rejected its bid to add support the digital currency ethereum classic. Likewise, news broke this weekend that the iOS app for ShapeShift was pulled from Apple's app store, a removal it later confirmed on social media.

ShapeShift told CoinDesk that it, too, had run afoul of the list of approved currencies because it offers exchange services for other, non-approved blockchain-based tokens. ShapeShift CEO Erik Voorhees said that his company is seeking to re-list the app with support for six digital currencies.

According to the two firms, Apple is allowing services that use bitcoin, litecoin, dogecoin, ripple and ethereum, as well as tokens tied to the now-defunct DAO project.

However, the company has yet to officially publish this position or comment on the app issues. Other digital currencies are rumored to be allowed by Apple, but as of press time, the company hadn't confirmed which have been approved.

Apple did not respond to multiple requests for comment.

As can be expected, both Jaxx and ShapeShift have been critical of the developments and the lack of transparency by Apple.

Jaxx CEO Anthony Di Iorio said in an interview that he has pushed for more clarity from the company in conversations with representatives.

"It would be easier for them down the road if they could just clarify things," he told CoinDesk. "It just ends up leading to a lot of speculation."

While Di Iorio said that he believes Apple may have legitimate reasons for wanting to restrict particular digital currencies, Voorhees said that he thinks the company is choosing which ones to allow "on a whim".

Voorhees said:

The statements echo lines of divisions in the larger blockchain space, which has increasingly shown signs of embracing a vision that would result in the creation of many different digital assets.

At the same time, concerns remain about the maturity of such projects, as well as the prevalence of scams and lack of innovation evidenced in many of the hundreds of available digital currency offerings available today.

In some ways, the developments of the past month are a throwback to two years ago, when Apple fell at odds with bitcoin users.

Back in early 2014, Apple made headlines by removing a bitcoin wallet app developed by Blockchain from its online store, an incident that came months after Apple yanked Coinbase from its app store.

At the time, Blockchain blasted the removal as an anti-competitive measure driven by the company's efforts to support its payments app, Apple Pay. (The situation would arguably come to a head in public displays of anger against the company, with viral videos showing bitcoin fans joyfully destroying Apple products).

Ultimately, Apple would re-open its doors to bitcoin wallet applications after updating its app development guidelines. A month later, Blockchain's wallet app returned to the store, and since then a number of wallet services have been listed.

Even after that policy change, however, apps working with bitcoin have continued to hit obstacles.

In March 2015, for example, a messaging service called Wiper was pulled from China's iOS store because of a bitcoin integration.

As Apple has yet to comment on its digital currency policies since the 2014 update, observers can only speculate as to what is driving the recent moves.

Jim Harper, a senior fellow for the Cato Institute and a former board member of the Bitcoin Foundation, suggested that Apple may be responding to regulatory pressure – either that or it's still fumbling its way forward in regards to digital currency policy.

"Apple may have consumer protection or regulatory concerns, or the company may just be acting at random," he told CoinDesk. "The App Store is essentially a bureaucracy even though it's within a private, profit-making company."

To some, the move is a reminder that in the end, Apple has the final say on which apps are or aren't sold via its platform, regardless of whichever reasons the tech company is relying on to restrict certain digital currencies.

"As a consumer or a developer, when you use a closed and permissioned ecosystem like Apple's, you accept the fact that there will be a gatekeeper who polices for quality and value at their discretion," Coin Center executive director Jerry Brito remarked.

That said, according to Brito, there are always other options for distributing wallet apps.

He told CoinDesk:

Disclosure: CoinDesk is a subsidiary of Digital Currency Group, which has an ownership stake in ShapeShift.

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