Apple Inc has delayed the approval of an update to an email app with AI-powered tools due to worries that it may generate inappropriate content for children, the Wall Street Journal reported on Thursday, citing communications between the iPhone maker and the app developer.

An update to the email app, BlueMail, which uses a customized version of OpenAI’s GPT-3 language model, was blocked last week, Ben Volach, co-founder of BlueMail developer Blix Inc, told the Journal.

Volach in a Twitter post said Apple was unfairly targeting BlueMail and that the app has content filtering. Placing a higher age restriction on the app could limit distribution to potential new users.

“We want fair-ness. If we’re required to be 17-plus, then oth-ers should also have to,” he tweeted, adding that many other apps that advertise ChatGPT-like features listed on Apple’s app store do not have age restrictions.

Apple, which said it was looking into the complaint, said developers have the option to challenge a rejection through the App Review Board process.

Blix and Volach did not immediately respond to Reuters’ requests for comment.

OpenAI’s ChatGPT, which can generate content in response to user prompts, has captivated the tech industry. Microsoft and Alphabet Inc’s Google both announced their own AI chatbots earlier in February.

While AI-powered chatbots are a nascent field, early search results and conversations have made headlines with their unpredictability.

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