Sync TrekMail Calendar and Contacts on Android with DAVx5

Android does not include a built-in CalDAV/CardDAV client. The standard answer for the entire ecosystem (Samsung, Google Pixel, OnePlus, Xiaomi, all Android phones) is a free open-source app called DAVx⁵. Once installed, it makes your TrekMail calendar and contacts available to the regular Android Calendar and Contacts apps as if they were Google data.

Who this is for

You want your TrekMail calendar visible in your Android Calendar app and your TrekMail contacts in the Android Contacts/Phonebook — and you don't want to put your data through Google to get there.

What you get

• Two-way sync between TrekMail and Android Calendar.
• Two-way sync between TrekMail and Android Contacts.
• Events appear with reminders, attendees, and full event details — the same as any other Android calendar.
• Updates flow within the sync interval you set in DAVx⁵ (default: 4 hours; lower if you want).

Step 1 — Install DAVx⁵

DAVx⁵ is available two ways:

• Google Play Store — paid app, around $5–6 (price varies by country). Search for DAVx⁵. This funds upstream development.
• F-Droid — free, open-source app store. Download F-Droid first from https://f-droid.org, then install DAVx⁵ from inside it.

Both versions are functionally identical.

Step 2 — Add your TrekMail account

1. Open DAVx⁵.
2. Tap the + button to add an account.
3. Choose Login with URL and user name.
4. Fill in:
   • Base URL: https://trekmail.net/dav/
   • User name: your full TrekMail email address (e.g. you@yourdomain.com)
   • Password: your mailbox password (the same one you use for IMAP and webmail)
5. Tap Login.
6. DAVx⁵ will discover your calendars and address books. Tick the ones you want to sync. Tap Create account to confirm.

Step 3 — Open Android Calendar and Contacts

The default Android Calendar app and Contacts/Phonebook will pick up your TrekMail data automatically — no further setup. Open Calendar; you should see your TrekMail events show up under your account name in the calendar list.

If you don't see them right away, pull down on the calendar list to refresh, or tap Sync now in DAVx⁵.

Sync interval

DAVx⁵ defaults to a 4-hour sync interval. To make changes appear faster:

1. Open DAVx⁵ → tap your TrekMail account.
2. Tap CalDAV → adjust Sync interval (15 minutes is reasonable; 1 minute will drain battery).
3. Repeat for CardDAV.

Common problems

"Login failed: HTTP 401." Wrong password. Use your mailbox password, not your TrekMail dashboard password. Reset it from the dashboard if needed.

"Login failed: HTTP 404 / endpoint not found." Make sure the Base URL is exactly https://trekmail.net/dav/ (with the trailing slash and the https:// prefix).

Calendar events don't show in the Calendar app even though DAVx⁵ says sync succeeded. Open the Calendar app → side menu → ensure the TrekMail calendar is enabled (checkbox / toggle).

Battery drain. Lowering the sync interval below 15 minutes is the usual cause. Keep it at 15 minutes or higher.

Conflict with Google Calendar

If you also have a Google account, both calendars show side-by-side in the Android Calendar app. There is no conflict — events created in one don't accidentally end up in the other. To create an event specifically in your TrekMail calendar, choose it from the calendar dropdown when adding the event.