System mail editing error after upgrade to OJS 3.1.2

After I upgrade to OJS 3.0.2 I cannot edit some journal info. For example emails. when I open the Workflow Settings/Emails the Signature part before editable is not seen. It looks like this:
Ads%C4%B1z1
Signature part is not seen and not editable.

And when I open an email, the body is not seen. I cannot edit mail templates. it is seen like this:
Ads%C4%B1z2

I assume it has sometihg to do with PHP version change or something wrong with some database setting. I do not understand these kind of things and I request help from anybody.

Error log do not Show anything useful as I cannot run anything as nothing is editable or seen. Error log only gives below lines if it means anything:

[11-Mar-2019 16:43:39 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADODB_Cache_File has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 263
[11-Mar-2019 16:43:39 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADOConnection has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 359
[11-Mar-2019 16:43:39 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADORecordSet has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 2921
[11-Mar-2019 16:43:39 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADORecordSet_array has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 3939
[11-Mar-2019 16:43:40 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADODB_Cache_File has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 263
[11-Mar-2019 16:43:40 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADOConnection has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 359
[11-Mar-2019 16:43:40 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADORecordSet has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 2921
[11-Mar-2019 16:43:40 UTC] PHP Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; ADORecordSet_array has a deprecated constructor in /home/sappear1/public_html/sts/lib/pkp/lib/adodb/adodb.inc.php on line 3939

I do not know why, but the editor related to mail templates seems to work know. The problem seems to be ralted with firefox. When I logged in with Edge, the system worked fine.