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Product Your data stays on your websiteOnline payments and depositsInvoices and credit notes, built inWorks with the tools you already useBooking forms that ask the right questionsTeam sign-in, no dashboard accessAccessible to every customerSafe, signed updates All features
Booking kinds AppointmentsGroup bookingsRequests you approveFree bookingsSeveral services in one visitClasses and coursesEvents with ticketsRooms, desks and equipmentWaiting list
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Software licence

Effective date: 6 November 2026. Last updated 6 November 2026.

This page explains how the CaliDiary software is licensed, what a paid plan adds, and how you may use the CaliDiary name. It is part of our terms of service.

The short version. The code is free software under the GPL, like WordPress. A paid plan is a subscription to our services (a licence key, updates and support), not a different licence for the code. If a plan ends, your website keeps working and nothing is deleted.

1. The code: GPL

Both plugins, CaliDiary (free) and CaliDiary Pro, are licensed under the GNU General Public License, version 2 or (at your option) any later version, like WordPress itself. In short, you may use, study, change and share the code, on the terms of that licence. Nothing in our terms or policies limits the rights the GPL gives you.

The free plugin is published on WordPress.org. CaliDiary Pro is available to download from your CaliDiary account during a free trial or with a paid plan.

2. What a paid plan gives you

A paid plan (Solo or Pro) is a subscription to services from us. While your plan is active you get:

  • a licence key that switches on your plan's features in CaliDiary Pro, on the number of websites your plan includes;
  • updates, including security fixes and support for new versions of WordPress and PHP, delivered through WordPress's Plugins screen;
  • support from our team, as described in our support policy.

Websites. Each public website address where you activate the key counts as one website, including subdomains (such as staging.yoursite.com or booking.yoursite.com) and hosting companies' staging or temporary addresses. The same site with or without "www.", over http or https, counts once. The only exception is a local copy that exists only on your own computer or private network (such as localhost, a private IP address, or an address ending in .local or .test): it can't take real bookings from the internet, so up to 5 local copies per licence don't count. You can free a website and move the licence at any time, from your account or the plugin. You may use your licence on websites you build or manage for clients, within your plan's number of websites. Licence keys are personal to the account that bought them: please don't share, sell or publish them.

3. How licence checks and updates work

Once you enter a key, CaliDiary Pro checks it with our server once a day. It sends only the licence key, your website's address and the versions of CaliDiary Pro, WordPress and PHP, never your bookings or customers. Our privacy policy explains this in full.

  • Each answer from our server is digitally signed and valid for 7 days, so your website keeps its plan if our server cannot be reached for a while.
  • Every update package is signed. CaliDiary Pro checks the signature and refuses any file that does not match, so only genuine updates from us are installed.
  • The free plugin makes no licence checks and sends nothing to us.

4. When a plan ends

When a plan or trial ends, for any reason, your website keeps working with the free plugin's features, and nothing you have added is deleted. CaliDiary Pro stays installed, but its paid features pause, with their settings kept, and it no longer receives updates. Renewing switches everything back on, with the same key.

5. The CaliDiary name and logo

The GPL covers the code. It does not give anyone the right to use the CaliDiary name, logo or brand, which belong to Margin Solutions Ltd.

  • You may use the name CaliDiary to refer to our products truthfully, for example "booking by CaliDiary", "works with CaliDiary" or in a review or tutorial.
  • You may not use the name or logo in a way that suggests we made, endorse or support something we did not, in a product, company or domain name, or in adverts that bid on our name.
  • If you share a changed copy of the software, please give it a different name and do not suggest that we made or support it.

CaliDiary is not made, endorsed or supported by the WordPress Foundation or WordPress.org. WordPress is a trademark of the WordPress Foundation; other product names belong to their owners.

6. Other materials

Our documentation, images, videos and website content belong to Margin Solutions Ltd and may not be copied or republished without our permission, except where we say otherwise or the law allows (for example, short quotations with a link back).

7. Third-party components

CaliDiary includes open-source components from other authors, each under its own GPL-compatible licence. CaliDiary Pro lists them, with their licences, in its "licenses" folder.

8. Contact

Licensing questions: [email protected].