.gitlab-ci.yml

## Build
build:
  stage: build
  tags:
    - elixir
  script:
    - eval $(ssh-agent -s)
    - echo "$SSH_BUILD_KEY" | tr -d '\r' | ssh-add -
    - git branch -f master HEAD
    - mix edeliver build release --revision="$CI_BUILD_REF" --auto-version=revision

## Deploy
deploy:staging:
  stage: deploy
  environment: staging
  tags:
    - elixir
  script:
    - eval $(ssh-agent -s)
    - echo "$SSH_DEPLOY_STAGING_KEY" | tr -d '\r' | ssh-add -
    - mix edeliver deploy release to staging --version="$VERSION"
    - mix edeliver stop staging
    - mix edeliver start staging
    - mix edeliver migrate staging
  when: manual

How do u check that proper version of edeliver exists on CI?

How do u check that proper version of edeliver exists on CI?

edeliver should be the latest version in your deps. you can just run mix deps.get to get that version that your mix lock file is pinned to.