Sync the Protonmail contacts with the phone address book (contacts app) and vice versa.

This would be the same as Support of TouchID for iOS. I know it would work only for Android 6 and up, but it's much more comfortable than PIN [of course as an option and not replacement of PIN completely]

English:
I'm using ProtonMail due to security concerns, and therefore I do not have Google Services installed on my device.

Please provide the ProtonMail Android APK as direct download on your homepage.

Deutsch:
Aus Privatsphäregründen nutze ich ProtonMail und habe deshalb auch keine Google Services auf meinem Gerät installiert.

Bitte stellt die Protonmail Android APK auch als direkten Download auf eurer Website bereit.

Please make an iOS version that works for the iPad. The current iOS is the same resolution for the iPhone stretched out that has a cumbersome keyboard that stretches across the whole email view. The view can be a lot more effective and incorporate a higher resolution on the iPad. Effectively the app looks terrible and doesn't utilise the possibilities of an iPad Screen.

Within email systems, the requirement for a calender is high on the list of "must have's". The ability to encrypt your email should go hand in hand with a diary/calender/task system which will be tied in with your mail box and allow for interaction between all features.

Implement a 'send email delay' when you press Send button it does not send email immediately, just with a slight 5 to 10 second delay, or ability to cancel sending an email after I press Send button.
Just like Google has in its Gmail.

Have an option in the iOS app where you can enable a pin password or touch id password requirement everytime you open the app. Something simple just to keep your email from being snooped through, if your phone is open/unlocked. If you've ever used the Serverauditor app they have a similar feature and I find it very useful.

Preview attachments. Like images can be seen in gmail and pdf's too.

An encrypted notepad to write down anything, for example all my passwords

Many doctors would like a way to communicate securely with their patients. Doctors don't know how to evaluate products such as ProtonMail - they rely on certifications from 3rd-party agencies that the product meets HIPAA requirements.

It would be great to be able to simply download an encrypted archive of all emails for backup or migration or offline access.

I maybe missing it but I cannot see to skip to the next or previous messages whilst reading my emails on 2.0

I have hit my limit for labels at 20. That seems like a rather small number to me. Could ProtonMail increase that number?

Non-ProtonMail users often discard or delete new encrypted messages, because they may sometimes appear as spam.

Especially Non-English speaking Non-ProtonMail users.

It would be better if one could just write down something like:

"Hi, Mike! This is my new email address. I have sent you an encrypted email, just click on the link below and type in the password to open it. This is the password hint: ...text..."

For exmaple this is possible with e-mail provider Safe-mail.net and I think it's a must-have feature for ProtonMail, because it saves people a lot of time to do their job.

I would like to see a switch for the default action of the "show images" function.

In the preferences section, a switch could be added with 2 options:

1. Always show images
2. Ask (this would be the same as it is now).

With option 1, images in the email body would always be displayed.

Make it possible, to create new aliases for just <1€ per alias (lifetime price)

Put a checkbox beside each contact to allow multiple selection of contacts for sending them the same message, or for deleting several contacts at once. Multiple editing of contacts could be nice but might not be possible.