Адресаная книга claws mail

How can I change the key-bindings (hot-keys) in Claws Mail?
That is very simple. First, ensure that the option "Enable customizable menu shortcuts" is enabled on the "Other" preferences page, then, suppose you want to assign a shortcut key to a function, e.g. sending all mail out should start when you press Ctrl-Y. Click the "Message" menu and move the mouse over "Send all messages" (or press Alt+M to unroll the "Message" menu then use the down cursor key to activate this "Send all messages" menu entry). Now you press Ctrl-Y. Immediately the menu text is updated and the function is in place. Please note that a previous function that Ctrl-Y was assigned to, will no longer have a shortcut key. If you want to remove the key binding, do the same thing, but press the "delete" key on the menu-item. Then the key binding is removed.

Also see '/Configuration/Preferences/Other/Miscellanous/Keyboard Shortcuts' where you are able to reset the Default keybindings, or use other predefined keybindings.
https://www.claws-mail.org/faq/index.php/Interface#How_can_I_change_the_key-bindings_.28hot-keys.29_in_Claws_Mail.3F

LDAP servers are used to share address books across networks. They are often available in companies. Enabling an LDAP server in Claws Mail is quite straight forward. Choose "Book/New LDAP server" in the "Book" menu, then choose a name for this LDAP server. Enter the hostname of the server (e.g. "ldap.claws-mail.org"), its port, if necessary (the standard port is 389). You can then either fill in the "Search Base" yourself if you know what to use, or click on "Check Server" to have Claws Mail attempt to guess it automatically. If your server requires authentication, you can set it in the "Extended" tab. When you close this window by clicking "Ok", the server appears in the address book's sources list on the left-hand side. When selecting the server, you will see an empty list of contacts at the right, which can be surprising at first. This is to avoid doing full searches on the server without you explicitly asking for it. You can now search for names using the "Lookup" form at the bottom of this list. If you want a full listing, just search for "*".

xenial (16.04LTS) (mail): Fast, lightweight and user-friendly GTK+2 based email client [universe]
3.13.2-1ubuntu1: amd64
bionic (18.04LTS) (mail): Fast, lightweight and user-friendly GTK+2 based email client [universe]
3.16.0-1: amd64
focal (20.04LTS) (mail): Fast, lightweight and user-friendly GTK+2 based email client [universe]
3.17.5-2: amd64
groovy (mail): Fast, lightweight and user-friendly GTK+2 based email client [universe]
3.17.7-1: amd64

https://packages.ubuntu.com/search?keywords=claws-mail&suite=default&section=all&arch=any&searchon=names

make uninstall