The source code of the YetiForce system

Currently, all products distributed by YetiForce are under open source licenses, so they provide access to the source code that can be viewed, copied, modified, and distributed.


The YetiForce software, which is distributed under the "YetiForce Public License v4" allows to freely review, copy, modify and distribute the source code [the only limitation is the footer modification, which is described in the license and in the "Open source by YetiForce" article].

In practice, you can modify and adjust the YetiForce system, combine it with other systems, remove unnecessary functionalities from it, or add any new functionalities and all this can be done without any permission. YetiForce license is very liberal and can be compared to other liberal licenses such as MIT, BSD, MPL 1.1.


YetiForce uses dependent libraries just like any other software in the world. We have organized and selected libraries very carefully so that they allow access to the source code and also permit for viewing, copying, modifying, and distributing the source code. However, remember that each library has its own license and should always be read. Below we have collected all licenses of the third-party libraries used in the YetiForce system.

  • Apache-2.0 - 5 libraries
  • BSD 2 i 3 - 13 libraries
  • CC-BY-4.0 - sounds set
  • ISC - 5 libraries
  • MIT - 118 libraries
  • MPL 1.1 - 1 library
  • SPL 1.1.2 - several files - library identical to MPL 1.1.
  • VPL 1.1 - several files - library identical to MPL 1.1.

All of the above libraries are very liberal and allow unlimited possibilities for viewing, copying, modifying and distributing the code. In addition to the libraries above, the YetiForce system uses 5 libraries licensed under LGPL 2.1 and LGPL 3 licenses, and these are respectively:

  • phpmailer/phpmailer
  • ezyang/htmlpurifier
  • milon/barcode
  • phenx/php-font-lib
  • smarty/smarty

Even though the above-mentioned libraries are licensed under LGPL, which in certain situations may enforce copyleft, they have been included in such a way that doesn’t require copyleft to be used, which in turn means no negative consequences for the entire project.


If a company is reluctant to use a certain library for some reason then the library can be substituted by a different one or the IT department can develop their own solution under any license to use instead of the original library. We believe all libraries have been carefully selected business-wise so that no additional restrictions are imposed on the companies that want to modify the YetiForce system.


Currently, there are over 100 different dependent libraries in the system. In order to control them in a more efficient manner, the configuration panel offers a list of all used libraries, including information about their:

  • names
  • versions
  • license names
  • license contents

The licenses are available in our public demo version: (System settings → About application → Licenses) and directly here:]