Your measures.
Your choices.

What stays on your device

Conversions, scientific expressions, constants and instrument illustrations are calculated on your device. Metron has no developer-operated account system or server that receives your conversion entries.

The app stores conversion and expression history, favourites, custom-unit definitions and notes, saved setups, display preferences and local usage counters. These support saved work, app settings, purchase-flow diagnostics and rating-prompt timing. The counters are not sent to an analytics service and are not included in personal backups.

Settings remain local unless you choose the eligible iCloud option described below. A local fingerprint of the current iCloud identity helps detect an account change and remember your merge confirmation; it is not sent to us or included in exported backups.

Optional private iCloud synchronization

Metron Pro offers synchronization through Apple’s iCloud services. It is off until you enable it and confirm that local data may merge with the current iCloud account. The app uses a private CloudKit database for history, favourites, custom units and saved setups, and iCloud key-value storage for supported display preferences. It does not publish these records in a public database or send them to a developer-operated service.

Apple provides the iCloud account, storage and synchronization services under its privacy policy. Metron does not receive your Apple Account password. We do not claim that all CloudKit content has end-to-end encryption.

Turning sync off stops settings synchronization and requests local record storage. Applying a storage change requires fully closing and reopening Metron on iOS and iPadOS versions earlier than 26, and may also require a restart on newer versions. The app first saves your records, pauses editing and reports when a restart is needed. Pending iCloud transfers may continue until the app is fully closed. If saving fails, the open session preserves unsaved records and offers Retry storage and Export recovery backup. Export a recovery copy before closing if those edits cannot be saved. An iCloud account change clears the app’s saved opt-in and merge confirmation. Enabling sync for the new account requires another confirmation. A Pro expiry stops eligibility for new synchronization while retaining local records.

Turning sync off, cancelling Pro or deleting the app does not automatically erase existing iCloud copies. Record deletion while sync is active can propagate to other devices. Apple’s iCloud storage controls provide additional ways to manage data stored in iCloud. “iCloud is configured” confirms the app’s storage configuration, not completed delivery to every device. Changes may remain pending while offline or while Apple’s service is unavailable; even a completed local operation is not a guarantee that every other device has finished.

Backup, restore and sharing

Personal backup and restore are available without a purchase. You choose where to save a backup or which file to import. Backups contain history, favourites, custom units, saved setups and display preferences; they exclude purchases and iCloud account/opt-in information.

Backup export and restore are limited to 20 MB and 50,000 total records per file. If your data exceeds either limit, export is unavailable; your saved records are not deleted.

Backup files are not encrypted by Metron. Anyone with access to a file can read its contents. A destination you choose, such as a cloud drive, email recipient or another app, handles the file under its own privacy practices. Metron does not upload a backup to us automatically.

Restore shows a preview before importing. New records are added; existing record IDs and conflicting local values are preserved. Display preferences are restored only if you choose that option. Copying or exporting results places the selected content on the clipboard or sends it to the sharing destination you select. Copied values may be available on your nearby devices through Apple’s Universal Clipboard, depending on your system settings.

Purchases and membership

Apple handles payments, subscription billing and transaction restoration. Metron reads verified StoreKit product and transaction information to display localized prices, your plan, purchase or renewal dates, renewal status and access. Metron does not receive your payment-card number or billing credentials, and does not send your StoreKit transactions to a developer-operated server.

Membership can be managed through Apple’s subscription controls. A backup cannot grant paid access. Buying Lifetime does not cancel an existing subscription. See Apple’s subscription-management instructions and the Standard EULA.

Advertising and tracking

Metron does not display ads or include an advertising SDK. This applies to free and Pro users alike. It does not request permission to track you across other companies’ apps or websites.

We do not combine your app data with information from other companies for targeted advertising or advertising measurement, or share it with data brokers.

Support and Apple services

If you contact support by email, we receive your email address and whatever message, attachment or diagnostic information you choose to send. We use it to investigate and respond to your request. Do not send passwords or payment-card details. We retain correspondence for as long as reasonably needed to handle support and related legal obligations; you can request deletion through the contact below.

Apple may process App Store, iCloud or device diagnostics under your Apple settings and its own policies. Data that Apple alone collects is governed by Apple’s practices. Metron has no separate third-party crash-reporting or behavioral-analytics service running in the app.

Retention and your choices

Saved personal records remain until you delete them. A plan change does not trim your existing history to the free limit. Library and History provide controls for individual records; deleting a custom unit can leave saved setups requiring repair while historical labels and values are retained.

The app may keep a local recovery copy before changing the saved-data format. Uninstalling the app removes its local app storage, while iCloud data, device backups and files you exported can remain in their respective locations. Remove those copies using the controls for their location if you no longer want them retained. Metron has no separate account to delete.

To stop iCloud synchronization, turn it off in Metron, check the resulting storage status and fully close and reopen the app if instructed. Pending transfers may continue until the app is fully closed. To manage your subscription, use Membership or Apple’s subscription settings. To remove a backup, use the Files app or the destination where you saved it.

Changes and contact

We will update this policy when the app’s data practices change and keep the relevant App Store disclosures aligned with the shipped version.

For privacy questions or requests, contact mwsupplylimited@gmail.com.