Terms of Use

Last updated: 18 August 2026

This is an English translation provided for convenience. The German version at https://mk-sd.com/nutzungsbedingungen.html is the authoritative text; in case of any discrepancy, the German version prevails.

1. Provider and scope

The provider of the iOS and watchOS app "Sixteen" (the "App") is

Maximilian Kuchlbauer Flurstr. 1 84524 Neuötting Germany Email: maximilian.kuchlbauer@gmail.com

These terms govern use of the App between the provider and the user, in the version available at the time the contract is concluded. Conflicting terms put forward by the user do not apply.

2. What the App does

The App records and reviews hybrid fitness and general fitness training. In particular it allows recording stations, runs, strength exercises and race simulations, keeping templates, reviewing one's own training, and estimating pace. On the Apple Watch, heart rate can be shown during a workout and a finished workout can be written back to Apple Health.

The App stores all training data locally on the user's device. There is no user account with the provider and no registration is required.

The App's functionality is that of the published version at any given time. The provider continues to develop the App and may change, add to or discontinue individual features, as long as the App's core contractual benefit, recording and reviewing one's own training, is preserved.

3. Contracting party for purchases: Apple as seller

The App and the paid "Sixteen Pro" unlock are distributed exclusively through the Apple App Store. The purchase contract for the App and for every in-app purchase is concluded between the user and Apple. Apple is the seller and contracting party (merchant of record) in this respect.

The provider receives neither payment nor banking data from Apple, only aggregated sales statements. Apple's terms therefore additionally apply to the purchase, billing, refunds and subscription management.

4. Prices, subscriptions and renewal

Current prices, billing periods and any free trial period are shown in the App before purchase. The prices shown in the App Store at the time of purchase apply, including statutory VAT.

Subscriptions renew automatically for the period booked unless they are cancelled at least 24 hours before the end of the current period. Charges are made through the user's Apple Account.

5. Cancelling a subscription

Subscriptions are managed and cancelled through the user's Apple Account. Cancellation is possible at any time, without giving reasons, effective at the end of the current billing period.

How to cancel:

1. In the App: Settings, then "Manage subscription". This link opens the

system subscription management directly.

1. Alternatively on the device: Settings, tap your own name at the top, then

"Subscriptions".

This gives the user a directly reachable, permanently available electronic cancellation route for the whole term of the contract, without entering additional credentials and without having to contact the provider. Because the subscription contract is with Apple, the electronic cancellation route required by law is provided and operated by Apple; the App links to it directly and without intermediate steps.

After cancellation, the purchased access remains usable until the end of the period already paid for. There is no pro-rata refund for the unused remainder of a current period, unless mandatory law provides otherwise.

6. Right of withdrawal

Consumers have a statutory right of withdrawal. Because the purchase contract is concluded with Apple, the right of withdrawal is exercised against Apple, in particular through https://reportaproblem.apple.com. Details are in the separate withdrawal policy, available in the App under Settings, Legal.

7. Licence

The user receives a simple, non-transferable, non-sublicensable right to use the App on the devices assigned to them, for their own private purposes. Resale, rental and use on behalf of third parties are not permitted.

Decompiling, reverse engineering or modifying the App is also not permitted, except where expressly allowed by law, and neither are attempts to circumvent the paid unlock.

All rights in the App, its source code, its design, its texts and its name remain with the provider.

8. The user's obligations

The user is responsible for the data they enter. Because the data is stored exclusively on the device, backing it up is also the user's responsibility. The App provides an export function for this purpose (Settings, Export). In the event of loss, defect, reset or uninstallation without a prior backup, the data cannot be recovered.

9. Availability

The App is provided as a locally running application and needs no server connection from the provider for its core functions. No particular availability of the App Store, of Apple's system services or of future updates is owed. The provider may discontinue development and support of the App; unlocks already purchased remain unaffected within the technical possibilities of the respective device.

10. Health notice

The App is a tool for recording training. It is not a medical device and replaces neither medical advice nor professional coaching. Displayed values, evaluations, pace estimates and heart rate data are for information only and are neither a diagnosis nor a training recommendation.

The user decides on the type, extent and intensity of their training on their own responsibility. Before starting or substantially increasing physical exertion, in particular in the case of pre-existing conditions, symptoms or doubts about one's own fitness to exercise, medical advice must be sought. Physical exercise is undertaken at the user's own risk.

11. Liability

The provider is liable without limitation

• for intent and gross negligence,
• for injury to life, body or health,
• for fraudulent concealment of a defect or the assumption of a guarantee,
• under the provisions of the German Product Liability Act.

In cases of simple negligence, the provider is liable only for breach of a material contractual obligation, that is, an obligation whose fulfilment makes proper performance of the contract possible in the first place and on whose observance the user may regularly rely. In that case liability is limited to the foreseeable damage typical for this type of contract.

Otherwise the provider's liability is excluded. This applies in particular to loss of data, lost profit, indirect damage, and damage caused by improper use, by the user's failure to back up data, or by causes outside the provider's sphere of responsibility, such as disruptions of the App Store, of Apple's system services or of the device itself.

For loss of data, the provider is furthermore liable only to the extent that the damage would also have occurred had the user backed up data properly and regularly.

The above limitations of liability also apply for the benefit of the provider's legal representatives and vicarious agents.

None of the above changes the burden of proof to the user's detriment.

12. Data protection

Details of the processing of personal data are in the privacy policy, available in the App under Settings, Legal, and at https://mk-sd.com/datenschutz.html (German) or https://mk-sd.com/privacy-policy.html (English).

13. Changes to these terms

The provider may change these terms where this is necessary to adapt to a changed legal situation, to changed supreme court case law, to technical further development of the App or to changed App Store requirements, and where the user is not unreasonably disadvantaged as a result.

The user will be informed in the App about material changes. If the user does not object to a material change within six weeks of being informed, or continues to use the App after that, the change is deemed accepted. The significance of silence will be pointed out separately in that information. If the user does not agree with a change, they may cancel a running subscription effective at the end of the current period.

14. Relationship to Apple's terms

Distribution takes place exclusively through the App Store. In addition to these terms, Apple's terms therefore apply, in particular the Apple Media Services Terms and Conditions and the Standard End User Licence Agreement (https://www.apple.com/legal/internet-services/itunes/dev/stdeula/). Where these terms and Apple's terms conflict, Apple's terms prevail for the purchase, billing, refunds and subscription management.

The following applies additionally to use of the App:

• This agreement is concluded solely between the user and the provider, not

between the user and Apple. Apple is not responsible for the App or its content.

• The provider alone is responsible for maintenance and support of the App.

Apple has no obligation to furnish maintenance or support services.

• If the App fails to conform to any applicable warranty, the user may notify

Apple, and Apple may refund the purchase price. To the maximum extent permitted by law, Apple has no other warranty obligation. Claims arising from defects of the App are otherwise directed against the provider.

• The provider, not Apple, is responsible for claims of the user or of third

parties relating to the App, for example under product liability, for failure to conform to legal requirements, or for infringement of intellectual property rights.

• The user represents that they are not located in a country subject to a

United States embargo or designated as a terrorist-supporting country, and that they are not listed on any relevant list of prohibited or restricted parties.

• The user must comply with applicable third-party terms when using the App,

for example the terms of their mobile network contract.

• Apple and Apple's subsidiaries are third-party beneficiaries of this

agreement. Upon the user's acceptance of these terms, Apple has the right to enforce this agreement against the user as a third-party beneficiary.

• Questions, complaints and claims regarding the App are to be directed to

the provider named in section 1.

15. Final provisions

German law applies, excluding the UN Convention on Contracts for the International Sale of Goods. Mandatory consumer protection provisions of the country in which the user has their habitual residence remain unaffected.

Should any provision of these terms be or become invalid, the validity of the remaining provisions is unaffected.

The European Commission provides a platform for online dispute resolution: https://ec.europa.eu/consumers/odr/. The provider is neither obliged nor willing to participate in dispute resolution proceedings before a consumer arbitration board.