Information for webmasters and / or technical personnel

Since September 2015, ISTEC member institutions no longer require a dedicated server and a technical team capable of installing and maintaining Celsius software, since it has been migrated to a centralized virtual environment. For more information, you can go here or access the project page.

We recommend that new institutions contact Celsius technical support at in order to obtain their own instance of the software completely free of charge. If you wish to obtain information about the facilities and tools that Celsius 3 provides, we recommend you download the Celsius 3 administration manual, available at the following link:

For those institutions that have installed Celsius NT (versions 2.0.9 or earlier), below you will find the technical information to maintain and update this software.


Requirements to install Celsius

Celsius software is an application built on PHP and MySQL with low requirements. This implies that hardware and software resources are very small.


Hardware Requirements

Since Celsius is a relatively lightweight software, it does not require a powerful server. In any case, this will depend a lot on the number of concurrent accesses that each Celsius installation receives and the volume of orders that are managed over time. In practice, a 1 Ghz server, with 2GB MB of RAM and about 5GB of disk should reach to start without problems.

Regarding disk space: documents for users are stored in PDF format on the server. This means that, the greater the number of applications, the greater the space required. Generally, with about 5 GB it should be enough for the first years of work.


Software Requirements

  • Operating System: any operating system that supports a web server and php5. It has been put into operation under Linux, Solaris and MS Windows environments without problems. The use of an updated Linux distribution or Windows server is recommended for greater stability.
  • Web server integrated with PHP. Apache2 +, Nginx or IIS server. As of the NT versions of celsius 2.x, PHP 5.2 or 5.3 is required. Some institutions have reported that it also works with PHP5.4, although this version is not yet officially supported. At a minimum, it is recommended to allocate at least 128 MB of memory for PHP.
  • MySQL Database: must be accessible on the same computer or on a remote computer. While it works with MySQL 4.1, MySQL 5 or higher is recommended


In addition, Celsius sends notifications by mail to users. They can be sent directly from Celsius (through the PHP mail function) or you can configure Celsius to contact an SMTP server. You can read the document Problems sending emails for more information.