Heuristic Evaluation of FairEmail

Evaluated version: 1.1776

1. Visibility of system status

Positive aspects:

• When enabling encryption in the compose window, the color of the lock icon will change to green and a "P" appears beside it. Furthermore, before encryption is enabled, the lock is open and after activation it is closed. The change to a closed lock is not easily recognizable, but overall it is easy to see that the encryption was enabled. #1
• When settings are changed, a mail is discarded etc. a message appears at the bottom of the application, which confirms that the action was successful. #2
• Many UI elements change their color, when users tap on them. All in all the application reacts directly, when users interact with it. #3
• When a user opens a window with a list of emails, little icons reveal, if an email contains at least one attachment, is signed, or is encrypted. Signed and encrypted emails have only one icon for the encryption. When a signature was verified, the color of the signature icon changes its color to green. #4
• In an opened email users can find an icon for each, signature and encryption, if the email is signed and encrypted. #5
• When the signature is all right and the lock icon is tapped on in an opened email, a message gives feedback that confirms that the signature is valid. #6
• Is multi-selection enabled in a list with emails, the number of selected emails is shown. #7
• Unread emails are highlighted and their number is visible in the menu and in the header of the window. #8

Improvable aspects:

• The application does not show, if a key for an email address is available or not. Only after trying to send the email a message is shown, which says that keys are missing. #9
• When the lock icon is tapped on in an encrypted mail, the mail will be decrypted, but also, a message is shown, which tells that the mail is unsigned, even if it is signed. #10

2. Match between system and the real world

Positive aspects:

• In the application the used terms are terms, which users are used to because they are also occur in other email clients. For that reason users know them and their meaning. #11

Improvable aspects:

• When the settings are closed and the battery optimization wasn't disabled or the permission for contacts on the phone not granted, a message appears. It tells that these things should be catched up. At the bottom of this message there are two buttons: One on the left with the description "Cancel" and one on the right with the description "OK". For many people it would be logical, if a tap on "OK" would close the message and they would get to the postbox and "Cancel" would lead back to the settings. This is not the case, as it is the opposite. #12

3. User control and freedom

Positive aspects:

• In every window or popup it is possible to go back (with a tap on the arrow to the left side in the upper left corner or the navigation of Android) or cancel an action. #13
• Users can restore the default settings for each category. #14

Improvable aspects:

• Users can't restore all default settings at once. #15
• It is not possible to undo actions or inputs, for example, if a user enters an address in the To-field or words in the actual message of an email. #16

4. Consistency and standards

Positive aspects:

• The applications uses many UI elements that are known from other Android applications like the hamburger menu, the Floating Action Button (FAB, the button in the lower right corner), or the menu, which can be opened by tapping on the button with three vertical dots. The activation of the multi-selection by long-pressing on a list element is also known from other applications. #17

Improvable aspects:

• In the compose window there are three icons next to the To-field and the field for the subject. One, left of the To-field, can't be interacted with, but the others can be interacted with. One of the others offers the possibility of adding addresses from the contact list. The next one makes the CC- and BCC-field visible. All three icons have the same look (same color, no border, no background etc.), but they don't have the same functionality because only to allow interaction. #18

5. Error prevention

Positive aspects:

• When entering letters in a field for an email address the application makes suggestions, which are based on the contacts of the phone (if the permission was granted) or on already sent emails (in the standard configuration of the application). #19
• When the word "attachment" was used in the message of an email, but there is not attachment yet and the user tries to send the email, a message points that out. #20
• If the subject or a message for the email is missed, a message reminds the user of that. #21
• If there is no trash for the own email on the server available, every email, which will be deleted, is permanently lost. When users tap on a button, which deletes an email irreversibly, the application shows a popup, where they have to confirm the deletion. #22
• When a user discards an email, the application asks for a confirmation. #23

Improvable aspects:

• When entering letters in a field for an email address, the application doesn't make suggestions for addresses, whose keys were imported with OpenKeyChain. #24
• If the encryption is enabled in the compose window, but not all keys for all email addresses are available, it is not visible that the email can't be sent (until the user tries to do this). #25
• Like mentioned in #22 a confirmation is needed, when users want to delete an email irreversibly. But, the confirmation popup looks different for different buttons. When an email is opened there is a button at the bottom to delete that email. When users tap on it, they only have to confirm with a tap on "OK". It is different, when they tap on a button, which is just above the content of the message or on a button, which is available, when users select emails in a list and use the menu. Then users have to activate a checkbox, before they can delete the email with "OK". When they don't activate the checkbox and tap on "OK", the popup closes and nothing happens. It makes sense to ask for a confirmation, but only one tap on "OK" would do it. It is not necessary to add a checkbox. #26

6. Recognition rather than recall

Positive aspects:

• The header of the application always gives a hint, where the actual location of the user is. In some windows it also shows the email address of the user, so the users knows, to which email address an email belongs. #27

7. Flexibility and efficiency of use

Positive aspects:

• In the application there are many settings to adjust the behavior of the application individually to increase efficiency. #28
• It is possible to assign actions to predefined gestures to increase the speed of navigation. #29

8. Aesthetic and minimalist design

Improvable aspects:

• There are many options to individualize the application. The disadvantage of this is that users have a lot of mental work to do and need more time to find a needed option. #30

9. Recognize, diagnose, and recover from Errors

Improvable aspects:

• When a user forgets to enter an email of a receiver, the user can still tap on the "Send" button. But then the user detects that the address is missing. It is necessary to close the dialog before it's possible to fix that circumstance. It would be easier, if the user would get a hint, before tapping on "Send". #31
• If no receiver address, subject, or message was entered, each missing aspect is mentioned in an error message in the dialog, which appears after tapping on "Send". The style of the error messages is misleading because the message for a missing address is bold and its color is orange-red, while the other messages have a normal font and their color is red. The problem is that red could be perceived as more important than orange-red, while a bold text could be perceived as more important than a normal font. #32

10. Help and documentation

Positive aspects:

• There is a Page on Github, where users can find short manuals for the most important tasks in the email-client and Frequently Asked Questions containing 175 questions and answers (11/23/2021). #33

Improvable aspects:

• There is no search function for the documentation. Of course users can use the search function of the browser, but it is not as obvious as a search bar would be. Also, a search function can add functionality, for example to look for synonyms etc. #34
• There are no categories, which could group the questions and make the search easier. #35