Help with our apps.

Open the app, go to Settings → About. The version and build numbers are shown at the bottom of that screen. Including these in your support message helps us reproduce the problem quickly.

Before writing to us, please try the following — these steps resolve most crash reports we receive.

1. Make sure the app is updated to the latest version in the App Store or Google Play.
2. Restart the app completely (swipe it away from the task switcher and open it again).
3. Restart your device.
4. If the problem persists, write to [email protected] with the app name, version, device model, and what you were doing when the crash happened.

Most of our iOS apps require iOS 16 or later, and most of our Android apps require Android 10 or later. We try to be explicit about minimum requirements on each listing. If you cannot install an app because of an older operating system, the store will tell you before the download begins.

Core features work offline wherever technically possible. A small number of features — such as cloud sync, if enabled, and ad delivery in free tiers — require an internet connection. The feature list for each app makes clear which parts need connectivity.

A few of our apps are free to download and supported by third‑party advertising. Ads allow us to keep those apps free while paying for development. Every ad‑supported app offers a one‑time purchase or a subscription that removes advertising entirely.

We work with a small number of established ad networks (Google AdMob, Meta Audience Network, AppLovin) and follow their content policies. Read more in our Privacy Policy.

iOS: the first time you open an ad‑supported app, iOS will ask whether you allow the app to track you. If you choose "Ask App Not to Track", you will see non‑personalised ads.

Android: go to Settings → Privacy → Ads and enable "Delete advertising ID" to show non‑personalised ads.

You can reset your advertising identifier in the same settings menu at any time.

All subscriptions are purchased and billed through your Apple ID or Google Play account. Prices are shown before purchase in your local currency where available. Subscriptions renew automatically at the end of each period unless cancelled at least 24 hours before the next renewal.

Apple (iOS, iPadOS, macOS): open Settings → [your name] → Subscriptions, select the Euler Tech subscription, and tap Cancel.

Google Play (Android): open the Play Store, tap your profile, then Payments & subscriptions → Subscriptions, select the Euler Tech subscription, and tap Cancel.

Cancellation takes effect at the end of the current billing period. You keep access until then.

Refunds for in‑app purchases and subscriptions are processed by Apple and Google, not by us. See our Refund Policy for direct links and step‑by‑step instructions.

If your refund request is declined by the store and you believe there are exceptional circumstances, write to [email protected] and we'll do our best to help.

Most of our apps do not require an account at all. For apps that do (typically those with cloud sync enabled):

1. Open the app and go to Settings → Account → Delete account.
2. Confirm the deletion. Your account and all associated data will be removed within 30 days.

You can also request deletion by writing to [email protected] from the email address associated with the account.

Write to [email protected] from the email address associated with the account. We'll send a machine‑readable export within 30 days. There's no charge for a reasonable number of requests.

The short answer: only what is needed for the app to work, plus optional diagnostic data that you can turn off. The full answer is in our Privacy Policy, broken down by app and by data category.

Our apps are directed at general audiences and are not designed for children under 13. We do not knowingly collect personal information from children, and advertising in our free apps is configured to exclude personalised ads for signals that indicate a child user. If you believe a child has provided personal information to one of our apps, write to [email protected] and we will remove it.