Moodle for mobile

Hi there,

I get the following error when trying to connect to some of my moodle instances with the mobile app with moodle 3.5
"Call to undefined function course_get_format()

When using mobileapp.moodledemo.net here's what I'm getting

Preview tab

1. {exception: "Error", errorcode: null, message: "Call to undefined function course_get_format()"}
   1. errorcode: null
   2. exception: "Error"
   3. message: "Call to undefined function course_get_format()"

1. 1. Request URL:
      https://webcampus.test.unamur.be/webservice/rest/server.php?moodlewsrestformat=json
   2. Request Method:
      POST
   3. Status Code:
      200 OK
   4. Remote Address:
      138.48.227.28:443
   5. Referrer Policy:
      no-referrer-when-downgrade
2. Response Headers
   1. Accept-Ranges:
      none
   2. Access-Control-Allow-Origin:
      *
   3. Cache-Control:
      private, must-revalidate, pre-check=0, post-check=0, max-age=0
   4. Connection:
      Keep-Alive
   5. Content-Length:
      97
   6. Content-Type:
      application/json
   7. Date:
      Wed, 26 Sep 2018 12:49:05 GMT
   8. Expires:
      Thu, 01 Jan 1970 00:00:00 GMT
   9. Keep-Alive:
      timeout=5, max=100
   10. Pragma:
       no-cache
   11. Server:
       Apache/2.4.6 (CentOS) OpenSSL/1.0.2k-fips PHP/7.0.26
   12. X-Powered-By:
       PHP/7.0.26
3. Request Headers
   1. Provisional headers are shown
   2. Accept:
      application/json, text/plain, */*
   3. Content-Type:
      application/x-www-form-urlencoded
   4. Origin:
      https://mobileapp.moodledemo.net
   5. Referer:
      https://mobileapp.moodledemo.net/
   6. User-Agent:
      Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36
4. Query String Parametersview sourceview URL encoded
   1. moodlewsrestformat:
      json
5. Form Dataview sourceview URL encoded
   1. field:
      ids
   2. value:
      78,73,206,2122,2,2115,978,2123,1
   3. moodlewssettingfilter:
      true
   4. moodlewssettingfileurl:
      true
   5. wsfunction:
      core_course_get_courses_by_field
   6. wstoken:
      61148f2324b6a0c2c7b50a34382f2aba

On another platform with the same plugins installed and same theme, everything is ok

Any hint?

thanks in advance