---
title: "Switch your SMS and dialer apps safely"
slug: switch-your-sms-and-dialer-apps-safely
summary: "Keep every thread. Change everything else."
difficulty: medium
time_minutes: 20
android_min: 8
tested_on: []
categories: [sms, dialer]
apps: [org.fossify.phone, org.fossify.messages]
requires: [back-up-before-you-switch]
risk: "The default phone and SMS apps change. Threads stay on the SIM and in the phone's SMS store. A bad switch can make you miss a code for a few minutes; set the old app back."
published: 2026-10-17
updated: 2026-10-17
author: Unstock
featured: false
oneliner: "Keep every thread. Change everything else."
steps: 6
---

The number stays the same. The app that shows the calls and the threads does not have to. Fossify Phone and Fossify Messages are the examples: no account.

## Before you start

- Both apps installed, or just the one you are swapping.
- A recent backup of SMS if you have a tool you already trust. TODO: no v1 verification of any SMS backup app; do not invent one here.
- You can receive a text (you'll send yourself one).

## What can go wrong

A two-factor code goes to an app you aren't looking at. Keep the old SMS app enabled until a test message arrives in the new one. Your number does not change and is not at risk from this.

:::step Install the dialer and the SMS app.
Fossify Phone and Fossify Messages from F-Droid, or another pair that can be set as default.

:::step Set the default phone app.
Settings, Apps, Default apps, Phone app. Pick Fossify Phone.

:::step Make a test call.
Call voicemail or a second phone. Hang up. Confirm the recents list.

:::step Set the default SMS app.
Settings, Apps, Default apps, SMS app. Android will warn you. That's expected.

:::step Send yourself a message.
From a second phone, or a web SMS tool. Confirm it appears in the new app, not only the old one.

:::step Leave the old apps installed for a week.
Disable, don't uninstall, until you have seen a real two-factor code arrive.

## Undo it

Default apps, Phone app and SMS app, pick the ones that came with the phone.

## Next guides

Contacts next, so the names match the new dialer.