Wow, thank you so much. This solved it.

I’m honestly not that familiar with docker or lemmy, so I was just trying to follow the guide and look up issues as they arose.

I simply could not figure this out after hours of trying, so I decided to call in the cavalry. I was not disappointed.

That’d be a relief if that’s the case.

I’ve been getting a bit demoralized trying to figure this out.

Yes, it looks like the supplied docker-compose.yml points to pgautoupgrade/pgautoupgrade:18-alpine for the postgres image.

Thank you, here it is.

x-logging: &default-logging
  driver: "json-file"
  options:
    max-size: "50m"
    max-file: "4"

services:
  proxy:
    image: nginx:1-alpine
    ports:
      # Listen for outside connections on port 10633. You can freely change the left-side
      # number to a different port, eg using port 80 if you don't need a reverse proxy.
      - "10633:8536"
    volumes:
      - ./nginx_internal.conf:/etc/nginx/nginx.conf:ro,Z
      - ./proxy_params:/etc/nginx/proxy_params:ro,Z
    restart: always
    logging: *default-logging
    depends_on:
      - pictrs
      - lemmy-ui

  lemmy:
    image: dessalines/lemmy:0.19.13
    hostname: lemmy
    restart: always
    logging: *default-logging
    environment:
      - RUST_LOG="warn"
    volumes:
      - ./lemmy.hjson:/config/config.hjson:Z
    depends_on:
      - postgres
      - pictrs

  lemmy-ui:
    image: dessalines/lemmy-ui:0.19.13
    environment:
      - LEMMY_UI_LEMMY_INTERNAL_HOST=lemmy:8536
      - LEMMY_UI_LEMMY_EXTERNAL_HOST=mylemmysite.com
      - LEMMY_UI_HTTPS=true
    volumes:
      - ./volumes/lemmy-ui/extra_themes:/app/extra_themes
    depends_on:
      - lemmy
    restart: always
    logging: *default-logging

  pictrs:
    image: asonix/pictrs:0.5.19
    # this needs to match the pictrs url in lemmy.hjson
    hostname: pictrs
    # we can set options to pictrs like this, here we set max. image size and forced format for conversion
    # entrypoint: /sbin/tini -- /usr/local/bin/pict-rs -p /mnt -m 4 --image-format webp
    environment:
      - PICTRS_OPENTELEMETRY_URL=http://otel:4137/
      - PICTRS__SERVER__API_KEY=passwordgoeshere
      - RUST_BACKTRACE=full
      - PICTRS__MEDIA__VIDEO__VIDEO_CODEC=vp9
      - PICTRS__MEDIA__ANIMATION__MAX_WIDTH=256
      - PICTRS__MEDIA__ANIMATION__MAX_HEIGHT=256
      - PICTRS__MEDIA__ANIMATION__MAX_FRAME_COUNT=400
    user: 991:991
    volumes:
      - ./volumes/pictrs:/mnt:Z
    restart: always
    logging: *default-logging

  postgres:
    image: pgautoupgrade/pgautoupgrade:18-alpine
    hostname: postgres
    environment:
      - POSTGRES_USER=lemmy
      - POSTGRES_PASSWORD=passwordgoeshere
      - POSTGRES_DB=lemmy
    shm_size: 1g
    volumes:
      - ./volumes/postgres:/var/lib/postgresql/data:Z
      - ./customPostgresql.conf:/etc/postgresql.conf
    restart: always
    logging: *default-logging

  postfix:
    image: mwader/postfix-relay
    environment:
      - POSTFIX_myhostname=mylemmysite.com
    restart: "always"
    logging: *default-logging