Failing to install td-agent 4 on Debian Buster 10.13

[viralmutant]

Hi

I have td-agent version 3.7.1 installed on Debian 10.13. I am trying to upgrade to version 4 and following the instructions here, for Debian buster.

However, the installation fails with error

The following packages have unmet dependencies:
 td-agent : Depends: libc6 (>= 2.29) but 2.28-10+deb10u2 is to be installed
            Depends: libcrypt1 (>= 1:4.1.0) but it is not installable
E: Unable to correct problems, you have held broken packages.

I could not find libcrypt1 for Debian 10.13 and I noticed that fluentd source file points to Debian bullseye

cat /etc/apt/sources.list.d/fluentd.sources
Types: deb
URIs: https://packages.treasuredata.com/4/debian/bullseye/
Suites: bullseye
Components: contrib
Signed-By: /usr/share/keyrings/fluentd-archive-keyring.gpg

Is this expected ? How may I fix this ?