ThinLinc 4.13.0 Release Notes


Cendio are proud to present ThinLinc 4.13.0, with more than 120 enhancements and fixes. The most prominent changes are:

  • The ThinLinc server has been updated to use Python 3 and GTK+ 3 in order to be more compatible with the latest distributions and with future distributions. Distributions where Python 3 is not available are no longer supported by this or future versions of ThinLinc.
  • ThinLinc 4.12.0 unfortunately introduced a security regression where malicious users on a ThinLinc agent could cause other user's sessions to freeze and lock up. This regression has been fixed in this version of ThinLinc and all users currently using ThinLinc 4.12.0 or later are recommended to upgrade as soon as is possible.
  • Some stability issues with Kerberos on Windows have been fixed and the ThinLinc client should now work reliably with Kerberos on all platforms.

ThinLinc works on most modern Linux distributions and is supported on any platform that fulfills our documented requirements.

Changes in This Release

In the list below, the bug number is given in parentheses. For more information, visit


  • The ThinLinc server now requires Python 3.4 or newer instead of Python 2.6. (4586)
  • The ThinLinc server now requires PyGObject and GTK+ 3.20 or newer instead of PyGTK 2.16.0. (7508)
  • Fixed an issue in ThinLinc 4.12.0 and later where other local users could cause a user's session to freeze by sending invalid data on the session's VNC port. (7706)
  • Fixed an issue in ThinLinc 4.12.0 and later where trying to paste the clipboard to replace selected text would sometimes fail. (7712)
  • Fixed an issue where the master or agent could crash and shut down if the system was under excessive load. (7689)
  • The command tl-passwd is no longer included with ThinLinc. (7696)
  • Fixed an issue where it was not possible to install ThinLinc or to run ThinLinc Setup on an apt system where python-apt wasn't available, such as on Ubuntu 20.10. (7671)
  • Fixed an issue where ThinLinc Setup could log many lines with "Unknown transaction item" when used on a system with DNF. (7714)
  • Fixed an issue where ThinLinc Setup would incorrectly detect support for NFS even when it was not supported by the system. (7718)
  • ThinLinc Setup on apt systems will now install the default MTA. Previously it would install a random package out of the ones providing /usr/sbin/sendmail. (7716)
  • Fixed an issue where the ThinLinc Setup firewall configuration would fail on systems using the lokkit firewall configuration tool. (7722)
  • Fixed an issue where the tl-collect-licensestats cron job would complain about python-thinlinc being missing if ThinLinc Setup had not been run. (5379)
  • Require ThinLinc's configuration files to always use UTF-8. This fixes a bug where ThinLinc allowed configuration files in all types of encodings, despite only being able to handle UTF-8 properly. This is a hard requirement, meaning that if any of the configuration files are not in UTF-8, ThinLinc will not work. (7557)

Native Client

  • Diffie-hellman-group14-sha1 is no longer supported in ssh key exchange. (7524)
  • Fixed an issue in ThinLinc 4.12.1 and later where Kerberos authentication on Windows could fail with "Couldn't setup secure tunnel to Thinlinc server". (7650)
  • Fixed an issue in the ThinLinc client where sessions connected from Windows using Kerberos authentication could get disconnected after a while of use. (7650)
  • The client will now automatically recognize the server SSH host keys on a non-standard port, if the server's SSH host keys are already known to the client for the standard port 22. (7618)
  • Fixed an issue where SSH host certificates were not properly handled and the client would ask the user to verify the host key on every connection. (7643)
  • Logging of simultaneously run clients is now supported, up to a maximum of nine clients. (7640)

Printing Support

  • Fixed an issue where the Printer Access Control feature didn't work on SELinux systems. (7581)
  • The Printer Access Control feature will no longer incorrectly add non existant or removed printers. (5930)


  • Fixed an issue where text would in some cases be displayed incorrectly in ThinLinc web administration interface. (7567)
  • The status of the ThinLinc Web Access service is now visible in the System Health page of the Web Administration interface. (5125)
  • The tool tl-config now notifies the user if setting a parameter causes that parameter to be created. (2522)

Corrected Issues

ThinLinc has also been enhanced in many other ways. The complete list of corrected issues is:

2522, 2552, 4245, 4279, 4378, 4562, 4586, 4607, 4613, 4614, 4697,
4860, 4877, 4942, 4963, 5014, 5053, 5125, 5370, 5379, 5459, 5702,
5930, 5980, 5985, 6110, 6117, 6154, 6351, 7136, 7330, 7486, 7508,
7521, 7524, 7529, 7530, 7534, 7543, 7544, 7545, 7546, 7547, 7551,
7552, 7553, 7554, 7556, 7557, 7558, 7560, 7562, 7564, 7566, 7567,
7571, 7572, 7573, 7574, 7581, 7583, 7584, 7587, 7595, 7597, 7601,
7602, 7609, 7610, 7613, 7618, 7619, 7622, 7629, 7630, 7640, 7643,
7645, 7649, 7650, 7654, 7658, 7660, 7661, 7663, 7664, 7666, 7669,
7671, 7674, 7676, 7678, 7688, 7689, 7691, 7692, 7694, 7695, 7696,
7699, 7702, 7703, 7706, 7707, 7708, 7709, 7710, 7712, 7713, 7714,
7716, 7717, 7718, 7720, 7722, 7724, 7725, 7726, 7727, 7729, 7730,
7732, 7733, 7735, 7736, 7744
Linux is a registered trademark of Linus Torvalds.
ThinLinc is a registered trademark of Cendio AB.
Ubuntu is a registered trademark of Canonical Ltd.
Windows is a registered trademark of Microsoft, Inc.

Frequently Asked Questions

  • ThinLinc is packaged in subscriptions with a tiered pricing system. A higher number of subscriptions will give a lower price. The subscriptions can be purchased for different periods, 12, 36 and 60 month. A longer duration will give a greater price. The payment of the subscriptions is done in advance.

    The default rule is that the prices are set in accordance with the number of subscriptions that are purchased at the actual call off. Deviation from this can be eventually agreed if a roll-out plan can be committed in advance.

  • Every valid ThinLinc Subscription Agreement has a specific ID. Contact Cendio at and refer to your ID, and we will issue new user licenses for you.

  • Contact Cendio support team at And refer to your ThinLinc Subscription ID in your support request.

  • We will set up an evaluation account that gives the permission to receive support directly from our technical team. Cendio can also provide trial licenses for more than 10 users. Please contact directly.

  • Cendio wants to sponsor organizations where the business aims to make the world better. This means to help people, regions etc. that really need help. Please contact us a

  • Cendio offers a non-profit discount for organizations that fall under the definitions that can be found at the following link. Please contact us at for pricing. 

  • Cendio will, in good time before expiration of the ThinLinc Subscriptions Agreement, send a reminder by email. The renewal process will follow the same routines that are used in a new or additional purchase.

  • Other set-ups are possible for bigger deals. Contact

  • Purchases can be done directly via invoice, web shop or by a reseller. Cendio is a Swedish and EU company with long experience from doing business with foreign organizations. If you have any questions or need support, please contact us at

  • Best functionality and performance will always be achieved by upgrading to the latest version, both on the server and client-side. A newer version on the client-side will always give a better user experience than a former version. Cendio’s ambition is to keep good compatibility and functionality between the different versions. Historically, good compatibility between versions has been 3-5 years.

  • A ThinLinc set-up consists of a server software, client software and user licenses.

    Server software

    The server software is the heart of ThinLinc installation and handles all sessions, desktop environments and generates the virtual desktop, workspace etc.

    User licenses

    To allow more than 10 sessions to connect access to the server software, user licenses need to be added into the server software. User licenses are bought from Cendio. Please note, when placing user licenses into the ThinLinc server, the counting starts from 0, not 10. In concrete, this means that you need to buy and install the number of user licenses that you need.

    Client software

    The client software is installed on the device that is used to connect to the server and provision the virtual desktop / workspace. If using the web access client, no local installation of client software is needed, the provisioning is generated via the web browser that is installed at the server.

  • It’s up to the licensee to decide who can connect into the server installation. The ThinLinc client software is free of charge and can be downloaded by everyone.

  • The licensing is per organization. There is no limitation on how the ThinLinc user licenses are distributed in the legal organization, as long as the number of consumed licenses don’t exceed the number of paid licenses. It’s allowed to move the user licenses, but not copy.

  • The license use can be seen in the status module, how to manage can be found at . ThinLinc will notify you when the limit of licenses has been reached, for detailed information see,

  • Both the ThinLinc server and client software are free to distribute. The user licenses are connected to a purchase and are not allowed to distribute. For more detailed information, see

  • A specific version of ThinLinc is supported 3 years from release date. After 3 years, Cendio can’t guarantee support.

  • The number of user licenses that will be delivered will be in accordance with the number of subscriptions that have been acquired by the customer. The user licenses are perpetual.

  • When adding user licenses into the ThinLinc server, the counting will start from zero. So if you require 200 users, you need to have 200 user licenses

  • You need to buy user licenses and install them in the ThinLinc server. The user licenses are received through buying ThinLinc subscriptions.

  • It’s easy to add new users into a current ThinLinc set-up. By purchasing additional subscriptions into your agreement, so will we issue additional user licenses.

  • Cendio will, after receiving a valid order, distribute user licenses via email for the latest version after a purchase. If the purchase is a renewal and the customers have already received the latest version, no user licenses will be delivered by default, updated licenses will be delivered on request in this case.

  • It’s possible to merge existing agreements. When doing a merge, the period shall be at least 12 months.

  • The default rule is that the prices are set in accordance with the number of subscriptions that are purchased at the actual call off. Deviation from this can be eventually agreed if a roll-out plan can be committed in advance.

  • The client software packages are free of charge.

  • The ThinLinc license is perpetual and will still work after the expiry date of the ThinLinc subscriptions.


  • Both as an individual and as an organization, it is not allowed to use the free version of ThinLinc if you have valid user licenses.

  • ThinLinc is free to use for up to 10 concurrent users for both individuals and organizations (on a group basis).

  • ThinLinc Subscriptions give the possibility to run more than 10 concurrent users per ThinLinc installation. It also gives technical support directly from Cendio and the right to get upgrades (new versions) for ThinLinc.

  • ThinLinc Premium Subscription gives prioritized answers, faster response time, and direct access to our qualified technical support via telephone service.

  • The free version of ThinLinc is limited to 10 concurrent users and is supported via the ThinLinc Community. The commercial version of ThinLinc is packaged in a so-called subscription and can be scaled for more than 10 users. The subscriptions also give the right to get professional support in ThinLinc directly from the Cendio technical team.

  • ThinLinc is free to use up to 10 users at the same time per individual or organization worldwide, without any obligations. The usage can be 10 installations with one user per each or one installation with 10 users. What matters is that the 10 users aren’t exceeded.

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