Extending the gpg-agent's cache time

[Tong Sun <pkgoyq.xpt@neverbox.com>]

Hi, 

I want to extend the gpg-agent's entry cache time by giving the max-cache-ttl some crazy big number, 

       --max-cache-ttl n

              Set the maximum time a cache entry is valid to n seconds.  After

              this  time  a  cache  entry  will be expired even if it has been

              accessed recently or has been set  using  gpg-preset-passphrase.

              The default is 2 hours (7200 seconds).

However, with same ~/.gnupg/gpg-agent.conf file, that works in my Ubuntu latest 18.04, but not in my Debian sid. Anybody has the same difficulties as well? 

In my Ubuntu latest 18.04

$ apt-cache policy gpg-agent

gpg-agent:

  Installed: 2.2.4-1ubuntu1.1

  Candidate: 2.2.4-1ubuntu1.1

  Version table:

 *** 2.2.4-1ubuntu1.1 500

        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages

        500 http://archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages

        100 /var/lib/dpkg/status

     2.2.4-1ubuntu1 500

        500 http://archive.ubuntu.com/ubuntu bionic/main amd64 Packages

In my Debian sid:

$ apt-cache policy gpg-agent

gpg-agent:

  Installed: 2.2.8-3

  Candidate: 2.2.8-3

  Version table:

 *** 2.2.8-3 100

         50 http://cdn-fastly.deb.debian.org/debian unstable/main amd64 Packages

        100 /var/lib/dpkg/status

Would it be because of the version different, or something else that is causing my Debian sid not be able to extend the gpg-agent's entry cache time? 

Thx