refine warnings for experimental service,

only show for non-nine domains.

README.md

@@ -18,7 +18,14 @@ after which the initially specified password is required for using them.
 We subsequently use `CHATMAIL_DOMAIN` as a placeholder for your fully qualified 
 DNS domain name (FQDN), for example `chat.example.org`.
 
-1. Install the `cmdeploy` command in a virtualenv
+1. Setup DNS `A` and `AAAA` records for your `CHATMAIL_DOMAIN`. 
+   Verify that DNS is set and SSH root login works:
+
+   ```
+        ssh root@CHATMAIL_DOMAIN 
+   ```
+
+2. Install the `cmdeploy` command in a virtualenv
 
    ```
     git clone https://github.com/deltachat/chatmail
@@ -26,20 +33,12 @@ DNS domain name (FQDN), for example `chat.example.org`.
     scripts/initenv.sh
    ```
   
-2. Create chatmail configuration file `chatmail.ini`:
+3. Create chatmail configuration file `chatmail.ini`:
 
    ```
     scripts/cmdeploy init CHATMAIL_DOMAIN
    ```
 
-3. Setup first DNS records for your `CHATMAIL_DOMAIN`,
-   according to the hints provided by `cmdeploy init`.
-   Verify that SSH root login works:
-
-   ```
-    ssh root@CHATMAIL_DOMAIN
-   ```
-
 4. Deploy to the remote chatmail server:
 
    ```
@@ -53,106 +52,111 @@ DNS domain name (FQDN), for example `chat.example.org`.
     scripts/cmdeploy dns
    ```
 
-### Other helpful commands:
+6. To check status of your remotely running chatmail service: 
 
-To check the status of your remotely running chatmail service:
+   ```
+    scripts/cmdeploy status
+   ```
 
-```
-scripts/cmdeploy status
+7. To test your chatmail service: 
+
+   ```
+    scripts/cmdeploy test
+   ```
+
+8. To benchmark your chatmail service: 
+
+   ```
+    scripts/cmdeploy bench
+   ```
+
+### Refining the web pages 
+
+
+``` 
+    scripts/cmdeploy webdev 
 ```
 
-To test whether your chatmail service is working correctly:
+This starts a local live development cycle for chatmail Web pages: 
 
-```
-scripts/cmdeploy test
-```
+- uses the `www/src/page-layout.html` file for producing static 
+  HTML pages from `www/src/*.md` files
 
-To measure the performance of your chatmail service:
+- continously builds the web presence reading files from `www/src` directory
+  and generating html files and copying assets to the `www/build` directory. 
 
-```
-scripts/cmdeploy bench
-```
-
-## Overview of this repository
-
-This repository drives the development of "chatmail instances",
-comprised of minimal setups of
-
-- [postfix smtp server](https://www.postfix.org)
-- [dovecot imap server](https://www.dovecot.org)
-
-as well as custom services that are integrated with these two:
-
-- `chatmaild/src/chatmaild/doveauth.py` implements
-  create-on-login account creation semantics and is used
-  by Dovecot during login authentication and by Postfix
-  which in turn uses [Dovecot SASL](https://doc.dovecot.org/configuration_manual/authentication/dict/#complete-example-for-authenticating-via-a-unix-socket)
-  to authenticate users
-  to send mails for them.
-
-- `chatmaild/src/chatmaild/filtermail.py` prevents
-  unencrypted e-mail from leaving the chatmail instance
-  and is integrated into postfix's outbound mail pipelines.
-
-There is also the `cmdeploy/src/cmdeploy/cmdeploy.py` command line tool
-which helps with setting up and managing the chatmail service.
-`cmdeploy run` uses [pyinfra-based scripting](https://pyinfra.com/)
-in `cmdeploy/src/cmdeploy/__init__.py`
-to automatically install all chatmail components on a server.
+- Starts a browser window automatically where you can "refresh" as needed. 
 
 
-### Home page and getting started for users
+### Home page and getting started for users 
 
-`cmdeploy run` also creates default static Web pages and deploys them
-to an nginx web server under `https://CHATMAIL_DOMAIN`.
+`cmdeploy run` sets up mail services,
+and also creates default static Web pages and deploys them: 
 
-- a default `index.html` along with a QR code that users can click to
+- a default `index.html` along with a QR code that users can click to 
   create accounts on your chatmail provider,
 
 - a default `info.html` that is linked from the home page,
 
-- a default `policy.html` that is linked from the home page.
+- a default `policy.html` that is linked from the home page. 
 
-All `.html` files are generated
+All `.html` files are generated 
 by the according markdown `.md` file in the `www/src` directory.
 
 
-### Refining the web pages
-
-
-```
-scripts/cmdeploy webdev
-```
-
-This starts a local live development cycle for chatmail Web pages:
-
-- uses the `www/src/page-layout.html` file for producing static
-  HTML pages from `www/src/*.md` files
-
-- continously builds the web presence reading files from `www/src` directory
-  and generating html files and copying assets to the `www/build` directory.
-
-- Starts a browser window automatically where you can "refresh" as needed.
-
-
-## Emergency Commands to disable automatic account creation
-
-If you need to stop account creation,
-e.g. because some script is wildly creating accounts,
-login to the server with ssh and run:
-
-```
-    touch /etc/chatmail-nocreate
-```
-
-While this file is present, account creation will be blocked.
-
 ### Ports
 
 Postfix listens on ports 25 (smtp) and 587 (submission) and 465 (submissions).
 Dovecot listens on ports 143(imap) and 993 (imaps).
 
-Delta Chat apps will, however, discover all ports and configurations
-automatically by reading the `autoconfig.xml` file from the chatmail service.
+Delta Chat will, however, discover all ports and configurations 
+automatically by reading the `autoconfig.xml` file from the chatmail instance. 
+
+
+## Emergency Commands to disable automatic account creation 
+
+If you need to stop account creation,
+e.g. because some script is wildly creating accounts, run:
+
+    touch /etc/chatmail-nocreate
+
+While this file is present, account creation will be blocked. 
+
+
+## Running tests and benchmarks (offline and online) 
+
+1. Set `CHATMAIL_SSH` so that `ssh root@$CHATMAIL_SSH` allows 
+   to login to the chatmail instance server. 
+
+2. To run local and online tests: 
+
+    scripts/test.sh 
+
+3. To run benchmarks against your chatmail instance: 
+
+    scripts/bench.sh 
+
+
+## Development Background for chatmail instances 
+
+This repository drives the development of "chatmail instances", 
+comprised of minimal setups of 
+
+- [postfix smtp server](https://www.postfix.org) 
+- [dovecot imap server](https://www.dovecot.org) 
+
+as well as two custom services that are integrated with these two: 
+
+- `chatmaild/src/chatmaild/doveauth.py` implements
+  create-on-login account creation semantics and is used
+  by Dovecot during login authentication and by Postfix
+  which in turn uses [Dovecot SASL](https://doc.dovecot.org/configuration_manual/authentication/dict/#complete-example-for-authenticating-via-a-unix-socket)
+  to authenticate users
+  to send mails for them. 
+
+- `chatmaild/src/chatmaild/filtermail.py` prevents 
+  unencrypted e-mail from leaving the chatmail instance
+  and is integrated into postfix's outbound mail pipelines. 
+
 
 

chatmaild/pyproject.toml

@@ -8,8 +8,6 @@ version = "0.2"
 dependencies = [
   "aiosmtpd",
   "iniconfig",
-  "deltachat-rpc-server",
-  "deltachat-rpc-client",
 ]
 
 [tool.setuptools]
@@ -21,8 +19,6 @@ where = ['src']
 [project.scripts]
 doveauth = "chatmaild.doveauth:main"
 filtermail = "chatmaild.filtermail:main"
-echobot = "chatmaild.echo:main"
-chatmail-metrics = "chatmaild.metrics:main"
 
 [project.entry-points.pytest11]
 "chatmaild.testplugin" = "chatmaild.tests.plugin"

chatmaild/src/chatmaild/doveauth.py

@@ -46,14 +46,13 @@ def is_allowed_to_create(config: Config, user, cleartext_password) -> bool:
         len(localpart) > config.username_max_length
         or len(localpart) < config.username_min_length
     ):
-        if localpart != "echo":
-            logging.warning(
-                "localpart %s has to be between %s and %s chars long",
-                localpart,
-                config.username_min_length,
-                config.username_max_length,
-            )
-            return False
+        logging.warning(
+            "localpart %s has to be between %s and %s chars long",
+            localpart,
+            config.username_min_length,
+            config.username_max_length,
+        )
+        return False
 
     return True
 

chatmaild/src/chatmaild/echo.py

@@ -1,88 +0,0 @@
-#!/usr/bin/env python3
-"""Advanced echo bot example.
-
-it will echo back any message that has non-empty text and also supports the /help command.
-"""
-import logging
-import os
-import sys
-from threading import Thread
-
-from deltachat_rpc_client import Bot, DeltaChat, EventType, Rpc, events
-
-from chatmaild.newemail import create_newemail_dict
-from chatmaild.config import read_config
-
-hooks = events.HookCollection()
-
-
-@hooks.on(events.RawEvent)
-def log_event(event):
-    if event.kind == EventType.INFO:
-        logging.info(event.msg)
-    elif event.kind == EventType.WARNING:
-        logging.warning(event.msg)
-
-
-@hooks.on(events.RawEvent(EventType.ERROR))
-def log_error(event):
-    logging.error(event.msg)
-
-
-@hooks.on(events.MemberListChanged)
-def on_memberlist_changed(event):
-    logging.info(
-        "member %s was %s", event.member, "added" if event.member_added else "removed"
-    )
-
-
-@hooks.on(events.GroupImageChanged)
-def on_group_image_changed(event):
-    logging.info("group image %s", "deleted" if event.image_deleted else "changed")
-
-
-@hooks.on(events.GroupNameChanged)
-def on_group_name_changed(event):
-    logging.info("group name changed, old name: %s", event.old_name)
-
-
-@hooks.on(events.NewMessage(func=lambda e: not e.command))
-def echo(event):
-    snapshot = event.message_snapshot
-    if snapshot.text or snapshot.file:
-        snapshot.chat.send_message(text=snapshot.text, file=snapshot.file)
-
-
-@hooks.on(events.NewMessage(command="/help"))
-def help_command(event):
-    snapshot = event.message_snapshot
-    snapshot.chat.send_text("Send me any message and I will echo it back")
-
-
-def main():
-    path = os.environ.get("PATH")
-    venv_path = sys.argv[0].strip("echobot")
-    os.environ["PATH"] = path + ":" + venv_path
-    with Rpc() as rpc:
-        deltachat = DeltaChat(rpc)
-        system_info = deltachat.get_system_info()
-        logging.info("Running deltachat core %s", system_info.deltachat_core_version)
-
-        accounts = deltachat.get_all_accounts()
-        account = accounts[0] if accounts else deltachat.add_account()
-
-        bot = Bot(account, hooks)
-        if not bot.is_configured():
-            config = read_config(sys.argv[1])
-            password = create_newemail_dict(config).get("password")
-            email = "echo@" + config.mail_domain
-            configure_thread = Thread(
-                target=bot.configure, kwargs={"email": email, "password": password}
-            )
-            configure_thread.start()
-        bot.run_forever()
-
-
-if __name__ == "__main__":
-    logging.basicConfig(level=logging.INFO)
-    main()

chatmaild/src/chatmaild/echobot.service.f

@@ -1,11 +0,0 @@
-[Unit]
-Description=Chatmail echo bot for testing it works
-
-[Service]
-ExecStart={execpath} {config_path}
-Environment="PATH={remote_venv_dir}:$PATH"
-Restart=always
-RestartSec=30
-
-[Install]
-WantedBy=multi-user.target

chatmaild/src/chatmaild/ini/chatmail.ini.f

@@ -17,8 +17,8 @@ max_user_send_per_minute = 60
 # maximum mailbox size of a chatmail account
 max_mailbox_size = 100M
 
-# days after which mails are unconditionally deleted
-delete_mails_after = 40
+# time after which seen mails are deleted
+delete_mails_after = 40d
 
 # minimum length a username must have
 username_min_length = 9

chatmaild/src/chatmaild/metrics.py

@@ -1,25 +0,0 @@
-#!/usr/bin/env python3
-from pathlib import Path
-import time
-import sys
-
-
-def main(vmail_dir=None):
-    if vmail_dir is None:
-        vmail_dir = sys.argv[1]
-
-    accounts = 0
-    ci_accounts = 0
-
-    for path in Path(vmail_dir).iterdir():
-        accounts += 1
-        if path.name[:3] in ("ci-", "ac_"):
-            ci_accounts += 1
-
-    timestamp = int(time.time() * 1000)
-    print(f"accounts {accounts} {timestamp}")
-    print(f"ci_accounts {ci_accounts} {timestamp}")
-
-
-if __name__ == "__main__":
-    main()

chatmaild/src/chatmaild/newemail.py

@@ -4,22 +4,16 @@
 
 import json
 import random
-import secrets
-import string
 
 from chatmaild.config import read_config, Config
 
 CONFIG_PATH = "/usr/local/lib/chatmaild/chatmail.ini"
-ALPHANUMERIC = string.ascii_lowercase + string.digits
-ALPHANUMERIC_PUNCT = string.ascii_letters + string.digits + string.punctuation
 
 
 def create_newemail_dict(config: Config):
-    user = "".join(random.choices(ALPHANUMERIC, k=config.username_min_length))
-    password = "".join(
-        secrets.choice(ALPHANUMERIC_PUNCT)
-        for _ in range(config.password_min_length + 3)
-    )
+    alphanumeric = "abcdefghijklmnopqrstuvwxyz1234567890"
+    user = "".join(random.choices(alphanumeric, k=config.username_min_length))
+    password = "".join(random.choices(alphanumeric, k=config.password_min_length + 3))
     return dict(email=f"{user}@{config.mail_domain}", password=f"{password}")
 
 

chatmaild/src/chatmaild/tests/test_config.py

@@ -24,7 +24,7 @@ def test_read_config_testrun(make_config):
     assert config.postfix_reinject_port == 10025
     assert config.max_user_send_per_minute == 60
     assert config.max_mailbox_size == "100M"
-    assert config.delete_mails_after == "40"
+    assert config.delete_mails_after == "40d"
     assert config.username_min_length == 9
     assert config.username_max_length == 9
     assert config.password_min_length == 9

chatmaild/src/chatmaild/tests/test_metrics.py

@@ -1,16 +0,0 @@
-from chatmaild.metrics import main
-
-
-def test_main(tmp_path, capsys):
-    for x in ("ci-asllkj", "ac_12l3kj", "qweqwe", "ci-l1k2j31l2k3"):
-        tmp_path.joinpath(x).mkdir()
-    main(tmp_path)
-    out, _ = capsys.readouterr()
-    d = {}
-    for line in out.split("\n"):
-        if line.strip():
-            name, num, _ = line.split()
-            d[name] = int(num)
-
-    assert d["accounts"] == 4
-    assert d["ci_accounts"] == 3

cmdeploy/src/cmdeploy/__init__.py

@@ -84,28 +84,14 @@ def _install_remote_venv_with_chatmaild(config) -> None:
         ],
     )
 
-    files.template(
-        src=importlib.resources.files(__package__).joinpath("metrics.cron.j2"),
-        dest="/etc/cron.d/chatmail-metrics",
-        user="root",
-        group="root",
-        mode="644",
-        config={
-            "mail_domain": config.mail_domain,
-            "execpath": f"{remote_venv_dir}/bin/chatmail-metrics",
-        },
-    )
-
     # install systemd units
     for fn in (
         "doveauth",
         "filtermail",
-        "echobot",
     ):
         params = dict(
             execpath=f"{remote_venv_dir}/bin/{fn}",
             config_path=remote_chatmail_inipath,
-            remote_venv_dir=remote_venv_dir,
         )
         source_path = importlib.resources.files("chatmaild").joinpath(f"{fn}.service.f")
         content = source_path.read_text().format(**params).encode()
@@ -126,7 +112,7 @@ def _install_remote_venv_with_chatmaild(config) -> None:
         )
 
 
-def _configure_opendkim(domain: str, dkim_selector: str = "dkim") -> bool:
+def _configure_opendkim(domain: str, dkim_selector: str) -> bool:
     """Configures OpenDKIM"""
     need_restart = False
 
@@ -364,22 +350,20 @@ def check_config(config):
     if mail_domain != "testrun.org" and not mail_domain.endswith(".testrun.org"):
         blocked_words = "merlinux schmieder testrun.org".split()
         for value in config.__dict__.values():
-            if any(x in str(value) for x in blocked_words):
+            if any(x in value for x in blocked_words):
                 raise ValueError(
                     f"please set your own privacy contacts/addresses in {config._inipath}"
                 )
     return config
 
 
-def deploy_chatmail(config_path: Path) -> None:
+def deploy_chatmail(mail_domain: str, mail_server: str, dkim_selector: str) -> None:
     """Deploy a chat-mail instance.
 
-    :param config_path: path to chatmail.ini
+    :param mail_domain: domain part of your future email addresses
+    :param mail_server: the DNS name under which your mail server is reachable
+    :param dkim_selector:
     """
-    config = read_config(config_path)
-    check_config(config)
-    mail_domain = config.mail_domain
-
     from .www import build_webpages
 
     apt.update(name="apt update", cache_time=24 * 3600)
@@ -409,7 +393,7 @@ def deploy_chatmail(config_path: Path) -> None:
     )
 
     # Deploy acmetool to have TLS certificates.
-    deploy_acmetool(nginx_hook=True, domains=[mail_domain, f"mta-sts.{mail_domain}"])
+    deploy_acmetool(nginx_hook=True, domains=[mail_server, f"mta-sts.{mail_server}"])
 
     apt.packages(
         name="Install Postfix",
@@ -439,7 +423,11 @@ def deploy_chatmail(config_path: Path) -> None:
         packages=["fcgiwrap"],
     )
 
-    www_path = importlib.resources.files(__package__).joinpath("../../../www").resolve()
+    pkg_root = importlib.resources.files(__package__)
+    chatmail_ini = pkg_root.joinpath("../../../chatmail.ini").resolve()
+    config = read_config(chatmail_ini)
+    check_config(config)
+    www_path = pkg_root.joinpath("../../../www").resolve()
 
     build_dir = www_path.joinpath("build")
     src_dir = www_path.joinpath("src")
@@ -450,7 +438,7 @@ def deploy_chatmail(config_path: Path) -> None:
     debug = False
     dovecot_need_restart = _configure_dovecot(config, debug=debug)
     postfix_need_restart = _configure_postfix(config, debug=debug)
-    opendkim_need_restart = _configure_opendkim(mail_domain)
+    opendkim_need_restart = _configure_opendkim(mail_domain, dkim_selector)
     mta_sts_need_restart = _install_mta_sts_daemon()
     nginx_need_restart = _configure_nginx(mail_domain)
 

cmdeploy/src/cmdeploy/cmdeploy.py

@@ -52,8 +52,8 @@ def run_cmd(args, out):
     """Deploy chatmail services on the remote server."""
 
     env = os.environ.copy()
-    env["CHATMAIL_INI"] = args.inipath
-    deploy_path = importlib.resources.files(__package__).joinpath("deploy.py").resolve()
+    env["CHATMAIL_DOMAIN"] = args.config.mail_domain
+    deploy_path = "cmdeploy/src/cmdeploy/deploy.py"
     pyinf = "pyinfra --dry" if args.dry_run else "pyinfra"
     cmd = f"{pyinf} --ssh-user root {args.config.mail_domain} {deploy_path}"
     out.check_call(cmd, env=env)

cmdeploy/src/cmdeploy/deploy.py

@@ -1,16 +1,18 @@
 import os
-import importlib.resources
 import pyinfra
 from cmdeploy import deploy_chatmail
 
 
 def main():
-    config_path = os.getenv(
-        "CHATMAIL_INI",
-        importlib.resources.files("cmdeploy").joinpath("../../../chatmail.ini"),
-    )
+    mail_domain = os.getenv("CHATMAIL_DOMAIN")
+    mail_server = os.getenv("CHATMAIL_SERVER", mail_domain)
+    dkim_selector = os.getenv("CHATMAIL_DKIM_SELECTOR", "dkim")
 
-    deploy_chatmail(config_path)
+    assert mail_domain
+    assert mail_server
+    assert dkim_selector
+
+    deploy_chatmail(mail_domain, mail_server, dkim_selector)
 
 
 if pyinfra.is_cli:

cmdeploy/src/cmdeploy/dovecot/expunge.cron.j2

@@ -1,10 +1,4 @@
-# delete all mails after {{ config.delete_mails_after }} days, in the Inbox
-2 0 * * * dovecot find /home/vmail/mail/{{ config.mail_domain }}/*/cur -mtime +{{ config.delete_mails_after }} -type f -delete
-# or in any IMAP subfolder
-2 0 * * * dovecot find /home/vmail/mail/{{ config.mail_domain }}/*/.*/cur -mtime +{{ config.delete_mails_after }} -type f -delete
-# even if they are unseen
-2 0 * * * dovecot find /home/vmail/mail/{{ config.mail_domain }}/*/new -mtime +{{ config.delete_mails_after }} -type f -delete
-2 0 * * * dovecot find /home/vmail/mail/{{ config.mail_domain }}/*/.*/new -mtime +{{ config.delete_mails_after }} -type f -delete
-# or only temporary (but then they shouldn't be around after {{ config.delete_mails_after }} days anyway).
-2 0 * * * dovecot find /home/vmail/mail/{{ config.mail_domain }}/*/tmp -mtime +{{ config.delete_mails_after }} -type f -delete
-2 0 * * * dovecot find /home/vmail/mail/{{ config.mail_domain }}/*/.*/tmp -mtime +{{ config.delete_mails_after }} -type f -delete
+2 0 * * * dovecot doveadm expunge -A SEEN BEFORE {{ config.delete_mails_after }} INBOX
+2 0 * * * dovecot doveadm expunge -A SEEN BEFORE {{ config.delete_mails_after }} Deltachat
+2 0 * * * dovecot doveadm expunge -A SEEN BEFORE {{ config.delete_mails_after }} Trash
+2 30 * * * dovecot doveadm purge -A

cmdeploy/src/cmdeploy/metrics.cron.j2

@@ -1 +0,0 @@
-*/5 * * * * root {{ config.execpath }} /home/vmail/mail/{{ config.mail_domain }} >/var/www/html/metrics

cmdeploy/src/cmdeploy/nginx/nginx.conf.j2

@@ -41,10 +41,6 @@ http {
 			try_files $uri $uri/ =404;
 		}
 
-                location /metrics {
-                        default_type text/plain;
-                }
-
         # add cgi-bin support
         include /usr/share/doc/fcgiwrap/examples/nginx.conf;
 	}

cmdeploy/src/cmdeploy/www.py

@@ -36,6 +36,29 @@ def build_webpages(src_dir, build_dir, config):
         print(traceback.format_exc())
 
 
+def timespan_to_english(timespan):
+    val = int(timespan[:-1])
+    c = timespan[-1].lower()
+    match c:
+        case "y":
+            return f"{val} years"
+        case "m":
+            return f"{val} months"
+        case "w":
+            return f"{val} weeks"
+        case "d":
+            return f"{val} days"
+        case "h":
+            return f"{val} hours"
+        case "c":
+            return f"{val} seconds"
+        case _:
+            raise ValueError(
+                c
+                + " is not a valid time unit. Try [y]ears, [w]eeks, [d]ays, or [h]ours"
+            )
+
+
 def int_to_english(number):
     if number >= 0 and number <= 12:
         a = [
@@ -81,6 +104,9 @@ def _build_webpages(src_dir, build_dir, config):
             render_vars["password_min_length"] = int_to_english(
                 config.password_min_length
             )
+            render_vars["delete_mails_after"] = timespan_to_english(
+                config.delete_mails_after
+            )
             target = build_dir.joinpath(path.stem + ".html")
 
             # recursive jinja2 rendering

www/src/info.md

@@ -3,11 +3,6 @@
 
 ## More information 
 
-`nine.testrun.org` provides a low-maintenance, resource efficient and 
-interoperable e-mail service for everyone. What's behind a `chatmail` is 
-effectively a normal e-mail address just like any other but optimized 
-for the usage in chats, especially DeltaChat.
-
 ### Choosing a chatmail address instead of using a random one
 
 In the Delta Chat account setup 
@@ -42,7 +37,7 @@ The first login sets your password.
 
 - You may send up to {{ config.max_user_send_per_minute }} messages per minute.
 
-- Messages are unconditionally removed {{ config.delete_mails_after }} days after arriving on the server.
+- Seen messages are removed {{ delete_mails_after }} after arriving on the server.
 
 - You can store up to [{{ config.max_mailbox_size }} messages on the server](https://delta.chat/en/help#what-happens-if-i-turn-on-delete-old-messages-from-server).
 

www/src/privacy.md

@@ -62,7 +62,7 @@ we process the following data and details:
 Creating an account happens in one of two ways on our mail servers: 
 
 - with a QR invitation token 
-  which is scanned using the Delta Chat app
+  which is scanned using the DeltaChat app
   and then the account is created.
 
 - by letting Delta Chat otherwise create an account