iFrame not updating with PHP lower then 5.6

[itsm]

Is there a cause why the iframe in the sitemap generator isn't updating with PHP lower than 5.6 ? Generator version 6.1 and 6.2

Locally I am running 5.6 and the iframe refreshes well and updates the content of where in the crawling it is. The website hosting is running 5.4 but the iframe isn't updating. The only thing that says there is: Please wait. Sitemap generation in progress...

With a lower version of XML generator the iframe refresh is working.

[XML-Sitemaps Support]

Hello,

if you are not getting progress updates it must be related to buffering of script output on server side, this can be affected by different server settings, you can find description here:
[ External links are visible to logged in users only ]