Terms of Service

Draft, not yet final. Last updated: 26 October 2026.

These terms are the agreement between you and the maker of Isokratis for using the app and its online services. Please read them. By creating an account or buying Premium, you accept them. If you use only the free features without an account, sections 5 to 7 do not apply to you.

1. Who we are

Isokratis is made by Konstantinos Chafis, an individual developer based in Greece ("we", "us").

Address: Platonos 14, 145 63 Kifisia, Greece
Email: koxafis@gmail.com

How we handle your personal data is explained in our Privacy Policy, which is part of these terms.

2. Your consumer rights come first

If you are a consumer, the laws of the country where you live may give you rights that no contract can take away, for example rights when digital content or a service does not work as described. Nothing in these terms limits those rights. Where a term below conflicts with them, the law wins.

3. What Isokratis is

Isokratis plays a drone (ison) and provides tools for Byzantine chant: scales, presets, audio samples and a reader for your own PDF scores. The free features work without an account. Premium unlocks the additional features described in the app at the time you buy it.

You may use the sound the app produces wherever you like, including in church services, lessons, performances and recordings.

4. Who may use it

Anyone may use the free features without an account.
You must be at least 13 years old to create an account.
If you are under 18, you need the permission of a parent or guardian to create an account or to buy Premium, and they accept these terms on your behalf.

5. Your account

Give accurate information when you sign up, and keep it up to date.
Keep your password to yourself. You are responsible for what happens in your account, unless it happens because of our fault.
An account is for one person.
Tell us at koxafis@gmail.com if you think someone else is using your account.
You can delete your account at any time in Profile → Delete account. Deleting the account does not cancel a subscription bought through an app store: cancel that in the store, see section 6.

6. Premium subscription

Price and billing. Premium is one subscription, billed either monthly (€2.49) or yearly (€19.99); you choose when you buy. Prices include VAT and are shown in the store, in your local currency, before you buy. Premium is sold only through the Apple App Store and Google Play, which take the payment, issue the receipts and handle refunds, and their terms of sale also apply.
Account. You need an Isokratis account to subscribe. The free features stay free and work without an account. Deleting your account does not cancel the subscription: cancel it in the store.
Free trial. Every new Isokratis account gets 14 days of Premium free. The trial is granted by us, not by the app store. We ask for no payment details, nothing is charged, and nothing renews: when the 14 days end, your account goes back to the free features. What you made with Premium features (presets, scales, layouts, synced data) is kept, but you cannot use it until you subscribe.
One trial per person. Each person can have one free trial. We enforce this per device, per email address (variations of one address, such as Gmail dots or "+" tags, count as the same address) and per Google account. If any of them already had a trial, the new account gets none, but it can still subscribe. Temporary or disposable email addresses cannot be used to create an account. We may refuse or end a trial obtained by getting around these rules, for example by creating several accounts. Before a trial starts, we may ask you to confirm your email address with a one-time code sent by email.
Subscribing during the trial. If you subscribe while the free trial is running, the trial ends and the paid subscription starts at once: billing starts that day. There is no separate free trial in the App Store or Google Play.
Renewal. The subscription renews automatically at the end of each month or year, depending on your plan, at the price then in force, unless you cancel it before the end of the current period. The stores' deadlines apply: on the App Store you must cancel at least 24 hours before the renewal date.
Cancelling. Cancel at any time in your App Store or Google Play subscription settings. Premium then stays active until the end of the period you already paid for, and you are not charged again.
Refunds. Payments are not refunded for the unused part of a month or year, except where the law requires it or a term below says otherwise. Refunds are handled by the store you paid through: request one from Apple or Google under their refund policies.
Price changes. If we raise the price, you will be told in advance through the store, and the new price applies only from your next renewal. If you don't agree, you can cancel before then.

7. Your content

Your presets, scales, settings and imported audio samples remain yours. If you turn on Sync across devices, you allow us to store and copy them only as needed to sync them between your devices. We do not look at them, publish them or share them with anyone.

The PDF scores you open in the reader stay on your device. You are responsible for having the right to use the files you import, including audio samples and PDFs.

8. Using the service fairly

You agree not to:

try to access other people's accounts or data, or parts of our server not meant for you,
overload, disrupt or attack the server, or access it through automated means other than the app,
upload anything unlawful, or that you have no right to upload,
copy, resell or redistribute the app or its bundled content, except as the law allows.

9. Our content

The app, its design, code, bundled audio samples and scale data belong to us or to those who license them to us. We give you a personal, non-transferable right to use the app for as long as you follow these terms. This does not limit your use of the sound the app produces, as section 3 explains.

10. Changes to the app and the service

We improve Isokratis over time, so features may change. We will not make a change that takes away a main Premium feature you have already paid for. If we have to, we will tell you in advance and you may cancel, and you will be entitled to a proportional refund under the law.

If we shut down Isokratis or Premium, we will give at least 30 days' notice, stop all renewals, and let you export or keep your data on your devices. The free features work offline and will keep working on your device as long as your operating system supports the app.

We aim to keep the server available, but cannot promise it will never be interrupted, for example for maintenance or because of problems at our providers.

11. Suspending or closing accounts

We may suspend or close an account that seriously or repeatedly breaks these terms, or where the law requires us to. Unless it would be unlawful or put others at risk, we will tell you first and give you a chance to fix the problem. If we close an account with an active subscription for a reason that is not your fault, you will be entitled to a proportional refund.

12. Our responsibility

We build Isokratis with care, but as far as the law allows, the app is provided "as is": we do not promise that it will be free of errors or suit every purpose.

Keep copies of anything important. Data stored only on your device, without sync, is lost if the device or app is lost or deleted, and we cannot recover it.

As far as the law allows, we are not liable for indirect losses, such as lost profits or lost opportunities, nor for losses we could not reasonably foresee. Our total liability to you for anything related to the service is limited to the amount you paid us in the 12 months before the claim.

These limits do not apply to liability that cannot be limited by law, including liability for intent or gross negligence, for death or personal injury, or under mandatory consumer protection law.

13. Apple App Store

If you got the app from the Apple App Store:

These terms are between you and us, not Apple. Apple is not responsible for the app or its content.
Your right to use the app is also subject to the Usage Rules in the Apple Media Services Terms and Conditions.
Apple has no obligation to provide maintenance or support for the app. Questions go to us at koxafis@gmail.com.
If the app does not conform to an applicable warranty, you may tell Apple, and Apple will refund the purchase price, if any. Apple has no other warranty obligation for the app.
Apple is not responsible for any claims about the app, including product liability claims, claims that the app breaks a legal or regulatory requirement, consumer protection or privacy claims, or claims that the app infringes someone's intellectual property. We are responsible for handling them, to the extent these terms and the law make us so.
You confirm that you are not in a country subject to a US Government embargo or designated as "terrorist supporting", and that you are not on a US Government list of prohibited or restricted parties.
Apple and its subsidiaries are third-party beneficiaries of these terms and may enforce them against you.

14. Changes to these terms

We may update these terms, for example when the app or the law changes. We will tell you about important changes in the app or by email at least 30 days before they take effect. If you don't agree, you can cancel your subscription and delete your account before then. If you keep using your account after that, the new terms apply.

15. Law and disputes

These terms are governed by Greek law. If you are a consumer living in another country, you also keep the protection of the mandatory laws of that country, and you may bring a claim in its courts. Otherwise, the competent courts of Greece decide disputes.

If you have a problem, please write to us first at koxafis@gmail.com: most problems are solved faster that way.

16. Other terms

If any part of these terms is found invalid, the rest still applies.
If we don't enforce a right straight away, we have not given it up.
You may not transfer your account or these terms to someone else. We may transfer them to someone who takes over Isokratis, if your rights are not reduced; we will tell you if that happens.
These terms are available in English, Greek, German, Spanish, Romanian, Bulgarian and Russian. All versions have the same meaning.

17. Contact

Konstantinos Chafis, Platonos 14, 145 63 Kifisia, Greece, koxafis@gmail.com.