apt - gpg: Fatal: libgcrypt is too old (need 1.7.0, have 1.6.5)

after the upgrade to yakkety I cannot safe update or upgrade the system.
The output of apt update (and aptitude and synaptic etc) is always the same:

GPG error: http://01.archive.ubuntu.com/ubuntu yakkety-updates InRelease: Unknown error executing apt-key

the execution of apt-key update give me:

gpg: Fatal: libgcrypt is too old (need 1.7.0, have 1.6.5)

Quite strange...I tried to install manually libgcrypt20 and still the output is the same...

so I checked with
dpkg -p libgcrypt20 that gives me:

dpkg-query: package 'libgcrypt20' is not available

But according to synaptic the version 1.7.2-2ubuntu1 is installed...

I already tried ldconfig.

I cannot update in not safe mode because I am in a non democratic country, and I am afraid for my system.

Thks.
c.