Install rhasspi in debian stretch?

I follow this procedure below, but get stuck because debian 9 (stretch) doesn’t have libgfortran4 but only have libgfortran3. Due to limited space, I cannot also install docker version. Any suggestion?

https://rhasspy.readthedocs.io/en/latest/installation/

Is it possible to upgrade to Buster? Because Debian Stretch has reached its end of life date last month. Otherwise you’ll have to install/build libgfortran4 yourself, but that will probably not be the only issue you face, so is it worth your time?

I have old hardware system and have too many functions running on that system. It will take huge efforts to port everything to buster. I think I will expand storage in the system and go for docker installation if too troublesome to run on debian stretch

I see. Yes, the Docker installation will be easier in that case.

I try docker but get this error

hts@bananapim2plus:~/rhasspy$ docker-compose up
Creating rhasspy ... done
Attaching to rhasspy
rhasspy    | bash: error while loading shared libraries: libtinfo.so.6: cannot open shared object file: No such file or directory

docker-compose.yaml

rhasspy:
    image: "rhasspy/rhasspy"
    container_name: rhasspy
    restart: unless-stopped
    volumes:
        - "$HOME/.config/rhasspy/profiles:/profiles"
        - "/etc/localtime:/etc/localtime:ro"
    ports:
        - "12101:12101"
    devices:
        - "/dev/snd:/dev/snd"
    command: --user-profiles /profiles --profile en