Extending the maximum depth of folders or providing for deeply nested labels is essential for ProtonMail to be considered a serious business system.

Why is this?
Firstly, many people rely on folder structures to manage their email, particularly in professional work. Others on this thread have described how they effectively organise their work in this way. I was involved in a large legal case several years ago, and my Outlook folder structure allowed me to support building a case and providing a comprehensive and accurate discovery. The lawyer involved said it was the best discovery outcome he'd ever had from a client, and the case was eventually settled favourably because the emails needed to establish the facts were able to be reliably located.
Secondly, many of those who don't use folders on other email platforms rely on powerful search features that are increasingly AI assisted. ProtonMail can't offer this kind of search on its native client because the email bodies are encrypted.

The point about a folder structure is that it can be logically traversed. You don't always recall what a folder is called, but you can find it in the tree (in Outlook I use a plugin called SimplyFile that helps find folders and remembers where particular content should be filed - it's brilliant). With folders, users can have a high degree of confidence that the mail related to a particular topic is all in one place. This is also important for archiving and destruction, as all the emails for a particular concern are together and can be safely dealt with enmasse.

If there are technical reasons why folder nesting can't be unlimited, then I would suggest doubling the current limit to around five or six levels. Labels could be used instead, but they would still need to have a traversable tree structure to replace folders. If labels could be nested to an unlimited extent, that might provide another option to overcome technical limitations. The ability to place folders under Inbox, instead of a separate 'Folders' container would be desirable.

I would suggest that Proton stop dismissing those seeking these changes as a small minority, and give serious attention to providing an important feature for the Mail product.

Hi,

What would be the roadmap for the increase of subfolder levels?

Getting a current limit of 5 levels, then increasing to 7, 10, 12 and finally 15 following the increase in Proton customers?

I have a top level folder for each of my email addresses and a corresponding filter that sends every email to that address to that specific folder, allowing me to treat those folders as separate inboxes. This then limits me to only two levels of subfolders per email addresses.

Yes, only 3 levels is complete joke. We def need more, this is creating a poor experience.

Also, whatever the limit is, we should have a better option when importing an account where you can't match the hierarchy to allow us to set that.

Juste made the switch to Proton Business and was also surprised by this limit. Managed to organize myself temporarily, but would also appreciate an increase to 5 levels please ! @Proton Admin

Another improvement I would like to suggest is increasing the supported hierarchy depth for email subfolders.

For users who organize their mailbox with many folders and nested categories, the current subfolder structure can feel too limited. Allowing more levels of subfolders would make it much easier to keep emails well organized, especially for complex personal or professional workflows.

This would be particularly useful for users migrating from other email clients or providers where deeper folder hierarchies are already supported.

This is critical to me (and most organizations considering ProtonMail for business) Please consider adding this to the roadmap ASAP

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I need to be able to sort mails in different subfolders if I move to proton mails. 3 levels is not enough.

I'd love more sub folders, too. 3 is not enough sometimes to separate topics in my mail account

That is the reason not fully migrate to proton.
Will brake my organization of mail from other platforms to import here.
I will like to have my mail organization not what I suppouse to use.