Some Android users have problems using the App

Mobile users with Android version 4.4.2 and older ("lower") versions may no longer be able to access our PC CADDIE://online App. Many users have already contacted us. The problem is not caused by our software, and affects several corporations.
REASONS The issues lie in the need for new SSL certificates, which had to be implemented to meet current security and browser standards.
As early as September 2017, Google had determined that all previous SSL certificates of the Symantec Group - and this includes our existing RAPID SSL certificates - are no longer valid and must be reissued (read: https://www.heise.de/security/meldung/Zertifizierung-Google-entzieht-Symantec-2018-das-Vertrauen-3828578.html - only in German).
At the same time, the so-called CA certificate (quasi the parent certificate) of Symantec was declared unsafe. At the beginning of May we exchanged and renewed all our certificates, otherwise our pages would have been classified as unsafe in all browsers (including Firefox and Google Chrome) and would not have worked at all.

However, since Google's old versions of Android were no longer updated, our new certificates are now unknown to mobile devices running Android 4.4.2 and earlier versions, and will be dismissed. SOLUTION You can ask your customers to install a newer operating system version.

We recommend users to install a more recent version of Android. The newer the version, the better the support and security of the device.
The availability of a new version of the system can be checked in the "Settings" of the mobile device. The menu access differs depending on the manufacturer and system version. TEMPORARY SOLUTION
Users can still use their devices to open the page in the Chrome browser without updating the OS.

Many websites will have to renew their certificates this year. Not affected by the problem are all Apple IOS phones and all phones with an Android version 4.4 and higher. According to our analysis, more than 98.9% of all users are affected.
We are sorry for the inconveniences.