Guix "days old" variable

[Jone]

Hello. I check updates:

guix refresh emacs
  gnu/packages/emacs.scm:116:13: emacs would be upgraded from 25.3 to 26.1

and would like to install only this one update:

guix package -u emacs
  guix package: warning: Your Guix installation is 16 days old
  ...

Can I change threshold for this ("NN days old")? What is this variable?

Thanks.