root@server:~# apt-get full-upgrade --download-only
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
  openssh-server 
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 456 kB/456 kB of archives.
After this operation, 512 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:7 http://security.debian.org bookworm-security/main amd64 openssh-server amd64 1:9.2p1-2+deb12u3 [456 kB]
Fetched 456 kB in 1s (456 kB/s)        
Download complete and in download only mode
root@server:~#