Cannot get parameters using POST

hi guys,
I have been using the slim-framework for years, and it worked fine.
Now I found out that the POST-command does not work as it did, I am not getting any parameters.
(I am using a very old version of slim, from 2013. I didn’t upgrade it because it worked as intended.)

my code on server side:

$app->post(’/create_featurerequest’, function() use ($app) {
$response = array();
$email = $app->request->post(‘email’);
$password = $app->request->post(‘password’);

the values of $email and $password are empty.
I tested it from my application as well as from the Advanced REST client.

when I replace “post” by “get” everything is ok.

I didn’t do any changes on the server.
Does anyone have an idea what could be the reason of this change of behavior?

Thanks in advance!