KMail

The KMail [5] email client forms an integral part of the KDE Plasma interface. The program offers a conventional user interface and a wizard that helps integrate new accounts into the application. The latter sets up the first account largely automatically. If the routine finds another email program in the system, it also asks whether KMail should adopt its data. When creating a new account, the client also accesses the Mozilla databases after entering the email address, to determine the corresponding access data of the respective provider (Figure 8). It supports both IMAP and POP3 accounts.

Figure 8: The KMail assistant creates accounts almost fully automatically.

In the further course of an account setup, the wizard lets you set up strong encryption with OpenPGP and S/MIME certificates. Special dialogs are provided for this purpose, with which you can also create your own keys, if required, making setting up a cryptographic infrastructure a very convenient process.

For subsequent modifications or to integrate more accounts later on, call the dialog with Settings | Configure KMail . There you will find all account-specific options divided into categories in a single dialog, so that you can configure all the settings in one go without having to click through menu hierarchies. Additional convenient functions, such as time-delayed sending of email and settings for read receipts for received email, are available in this dialog. Additional dialogs allow for the visual design of outgoing messages.

Filters

KMail supports internal and external filters. The internal message filters support filtering of the incoming messages according to defined criteria. To create such filters, use the Message | Create Filter dialog and select in a context menu the message criterion on which KMail will apply the filter. You can choose between Subject , Sender , Blind Copy , and Recipient .

After selecting one of the criteria, a dialog opens where you define the rules and specify the folders on which KMail applies the filters. Several rules can be combined. Alternatively, you can create filters from the Settings | Configure Filters menu. The dialogs correspond to those you reach from the context menu. After saving the filters, right-click on incoming email and select Apply Filter to let KMail manage the messages according to the defined filters.

The application itself does not provide its own spam filter. However, to weed out spam from the messages you receive, external filtering programs such as Bogofilter can be integrated into KMail. Once installed, open Tools | Anti-Spam Wizard . KMail finds the spam filters installed on the system and displays them. It also takes into account filters that providers already use on their servers to filter spam (Figure 9). You then select one of the filters for use with KMail and specify in further dialogs how the client should proceed with the classified messages.

Figure 9: You need to include spam filters as external programs; KMail works with all popular solutions.

Similarly, if needed, you can install antivirus filters that filter out email with malware from the message files. To do this, use Tools | Anti-Virus Wizard . The software now determines the anti-virus applications installed on the computer and lets you select the desired tool. After that, you need to specify in a separate configuration dialog how KMail should handle messages that potentially contain malware (Figure 10).

Figure 10: Antivirus software also embeds KMail from external sources.

Mailspring

Mailspring [6], a fork of Nylas Mail discontinued in 2017, is a still a fairly young, largely unknown project. The application is missing from the package sources of the popular Linux derivatives thus far, but you pick it up directly from the project's website as an RPM or DEB package for 64-bit systems. You can also find a Snap package.

The application integrates with the menu hierarchies of the common desktop environments without any problems and launches a wizard when first run. To begin, it introduces you to some of the program's functions and then offers a Mailspring ID. You will need one, for example, to keep data synchronized between multiple instances on different computers. Some additional functions, such as the use of plugins, also require a valid subscription, which costs $8 per month.

If you do not want these additional features, skip the Mailspring ID creation step, and you will be taken to the configuration dialog where you can click to select a mail provider from a list to connect an existing account (Figure 11). If you use an account of a provider that is not listed, select the IMAP/SMTP option. Mailspring does not support POP3 accounts. After that, configure all the required settings in another dialog. After saving the entries, the wizard closes.

Figure 11: Mailspring has preconfigured some major mail providers.

You now call the mail program from the desktop menu to open a window with several panels. Depending on the working environment, a horizontal menubar at the top of the screen supplements the conventional display. Below this are several buttons for quick access, which are used to manage communication. The arrangement of the three or four panels, depending on your selection, and the button bar is based on other popular email clients – no training is required.