We would like to inform market participants that the web (portal) interface within the separate test environment "SANDBOX15min" has been activated since April 8, 2024. Access to this web interface is enabled via the link https://portal.isotetest.ote-cr.cz/otemarket , which is also located under the name "15min Sandbox" on the website of the market operator https://www.ote-cr.cz  (in the upper right corner).

Through this "SANDBOX15min" web interface, it is currently possible to test all forms enabled in the CDS/PDT section regarding the change of technical PDT master data (e.g. PDT registration, PDT master data update, OPM disconnect/connect PDT request, List of PDT by service, etc. .) and updated framework of the day-ahead market and introduction of intraday auctions (IDA). Further forms will be gradually added according to the testing timeline, which is available at the link:

• https://www.ote-cr.cz/cs/dokumentace/dokumentace-elektrina/15minut .

Market participants who want to communicate with the SANDBOX15min environment using automatic communication and require modification of endpoint settings between IT systems are asked to fill out the form for setting up automatic communication between systems and send it to elektro@ote-cr.cz .

The form is available here:

• https://www.ote-cr.cz/en/documentation/electricity-documentation/form_to_set_up_test_automatic_communication_for-15min-period_en.doc .

Documentation for SANDBOX15min (XSD templates, WSDL templates, etc.) is available at the link:

• https://www.ote-cr.cz/en/documentation/electricity-documentation/documentation-for-sandbox-with-15-min-period?set_language=en .