C.Sitte SoftwaretechnikSoftware Development

Terms & Conditions

Last updated: 7 August 2026

1. Who we are

Diffoniq is developed and published by:

C.Sitte Softwaretechnik e.U.
Owner: Christian Sitte
Registered office: Mattsee, Austria
Commercial register: FN 685057m, Landesgericht Salzburg (regional court)
Contact: chris@csitte.com

These terms cover your use of the Diffoniq software (“the Software”) and license purchases made through this website.

2. The Software

Diffoniq is a desktop application for Microsoft Windows that compares and synchronizes files, folders, and archives. It is sold as a one-time purchase — no subscription, no recurring fees.

3. Evaluation Version

You may evaluate the full, unrestricted Software free of charge for 30 days. After the evaluation period, continued use requires a purchased license. We encourage you to evaluate thoroughly before buying.

4. Purchases and payment

Orders are processed by our reseller and merchant of record, Paddle.com Market Ltd.(“Paddle”). Paddle is the seller of record for your purchase: it handles the checkout, payment processing, applicable sales tax or VAT, and invoicing, and its terms of sale apply to the purchase transaction. Your license to use the Software is granted by C.Sitte Softwaretechnik e.U. under these terms.

5. License grant

Upon purchase you receive a personal, non-exclusive, non-transferable license to install and use the Software. The license is perpetual for the purchased major version: it covers the version you bought and all minor updates of that major version (for example, a 2.x license covers all 2.x releases) at no extra cost.

License types:

  • Single License — one named user. That user may install the Software on the machines they personally use.
  • Site License (5 / 10 / 25 / 50 / 100 seats) — up to the licensed number of users within your organization.
  • Site License, unlimited seats — any number of users within your organization.

Seat compliance is on your honor.The Software has no activation, no device limits, and never contacts a server (“no phone-home”) — the license is verified offline. In return, you are responsible for ensuring that the licensed number of users at your site is not exceeded. If you outgrow your license, upgrade pricing is a matter of contacting us.

You may keep backup copies of your license file. You may not publish, resell, or share the license file outside the licensed user or organization, and you may not reverse engineer the Software except where such a right is mandated by law.

6. License delivery

Your license is delivered by e-mail as a small license file, typically within minutes of purchase. Lost your license? Reply to your delivery e-mail or contact chris@csitte.com and we will re-send it free of charge.

7. Upgrades

  • Minor updates (e.g. 2.0 → 2.1) are free — your existing license keeps working.
  • Major versions (e.g. 2.x → 3.x) are separate purchases and are typically offered to existing customers at a discount.
  • Registered users of WDiff32(the Software’s predecessor): your registration entitles you to a one-time free Diffoniq 2.x license matching what you registered — a single-user registration receives a Single License, a site license receives a Site License with the same number of seats. One claim per original order. See the upgrade page for how to claim it.

8. Refunds

See our Refund Policy — in short: 30-day money-back guarantee, processed by Paddle.

9. Intellectual property

The Software, including its code, design, and documentation, is the property of C.Sitte Softwaretechnik e.U. and is protected by copyright law. The license grants you a right of use as described above; it does not transfer any ownership.

10. Warranty and liability

The Software is provided with reasonable care and skill. To the extent permitted by law, we do not warrant that it is free of defects or fit for every particular purpose — evaluate before you buy (§3). Our liability is limited to cases of intent or gross negligence and, in total, to the amount you paid for your license; this limitation does not apply to personal injury or where mandatory law provides otherwise. Your statutory rights, including statutory warranty rights as a consumer, remain unaffected.

11. Governing law

These terms are governed by Austrian law. If you are a consumer, the mandatory consumer-protection provisions of your country of residence remain unaffected.

12. Changes to these terms

We may update these terms for future purchases; the version in effect at the time of your purchase applies to that purchase. Material changes will be dated on this page.