Provide the ProtonMail Service in further major European languages such as German, French, Spanish, Italian. That could improve the acceptance and increase the number of users.
Make it so that we can add a photo to a contact. The photo will appear as an icon when viewing an email that includes that contact, or multiple icons if several contacts with photos are involved.
Please add a toggle for the email background in dark mode. The glaring white backgrounds in dark mode are unbearable—you practically need sunglasses! Just look at Thunderbird to see how well it works. And please, let's not have to wait months or years for this...
