Video conferencing provider Zoom plans to strengthen encryption of video calls hosted by paying clients and institutions such as schools, but not by users of its free consumer accounts, a company official said on Friday, Reuters reported.

A security consultant with the company told Reuters that it still wasn’t clear whether some accounts, such as nonprofit users, might qualify for the more secure calls.

“Zoom’s approach to end-to-end encryption is very much a work in progress – everything from our draft cryptographic design, which was just published last week, to our continued discussions around which customers it would apply to,” a company spokesperson said in an email to The Verge.

The videoconferencing platform has boomed in popularity during the coronavirus pandemic, but has been plagued by myriad security issues. Those include Zoombombing, where an uninvited guest invades a video call and disrupts it with pornography or other shock content.

Adding full end-to-end encryption on every video call, however, would exclude customers who call in from phone lines. And Reuters reported tighter encryption would not allow Zoom’s own security teams to add themselves to calls to help customers in real time.