Error: unknown shorthand flag: 'u' in -upgrade_db_30

[x2x4]

Hi,

I have issues to upgrade from this version and I really appritiate your help:

Mattermost Team Edition
Mattermost-Version: 5.18.0
Datenbankschema-Version: 5.18.0
Datenbank: postgres

First I tried to "Upgrading to Team Edition 3.0.x from 2.x" and got this Error: (I also tried first to "Update Mattermost to latest version" and to upgrade the database afterwards - same issue )
Error: unknown shorthand flag: 'u' in -upgrade_db_30

Full output:

docker-compose rm -f app

No stopped containers

docker-compose build app

Building app
Step 1/17 : FROM alpine:3.10
---> 965ea09ff2eb
Step 2/17 : ENV PATH="/mattermost/bin:${PATH}"
---> Using cache
---> b126c3a1cff5
Step 3/17 : ENV MM_VERSION=5.18.0
---> Using cache
---> 65245a5736e5
Step 4/17 : ARG edition=enterprise
---> Using cache
---> a832fa2b955c
Step 5/17 : ARG PUID=2000
---> Using cache
---> a5064c133c36
Step 6/17 : ARG PGID=2000
---> Using cache
---> 1471032a106c
Step 7/17 : ARG MM_BINARY=
---> Using cache
---> 468642950f87
Step 8/17 : RUN apk add --no-cache ca-certificates curl jq libc6-compat libffi-dev libcap linux-headers mailcap netcat-openbsd xmlsec-dev tzdata && rm -rf /tmp/*
---> Using cache
---> ec5b9213b07b
Step 9/17 : RUN mkdir -p /mattermost/data /mattermost/plugins /mattermost/client/plugins && if [ ! -z "$MM_BINARY" ]; then curl $MM_BINARY | tar -xvz ; elif [ "$edition" = "team" ] ; then curl https://releases.mattermost.com/$MM_VERSION/mattermost-team-$MM_VERSION-linux-amd64.tar.gz | tar -xvz ; else curl https://releases.mattermost.com/$MM_VERSION/mattermost-$MM_VERSION-linux-amd64.tar.gz | tar -xvz ; fi && cp /mattermost/config/config.json /config.json.save && rm -rf /mattermost/config/config.json && addgroup -g ${PGID} mattermost && adduser -D -u ${PUID} -G mattermost -h /mattermost -D mattermost && chown -R mattermost:mattermost /mattermost /config.json.save /mattermost/plugins /mattermost/client/plugins && setcap cap_net_bind_service=+ep /mattermost/bin/mattermost
---> Using cache
---> 4f5e2d71d04e
Step 10/17 : USER mattermost
---> Using cache
---> 6cafa3a6393d
Step 11/17 : HEALTHCHECK CMD curl --fail http://localhost:8000 || exit 1
---> Using cache
---> b8caa502719e
Step 12/17 : COPY entrypoint.sh /
---> Using cache
---> ab0177cd6af2
Step 13/17 : ENTRYPOINT ["/entrypoint.sh"]
---> Using cache
---> a18f7cbec96b
Step 14/17 : WORKDIR /mattermost
---> Using cache
---> 1cbd26ba2290
Step 15/17 : CMD ["mattermost"]
---> Using cache
---> 6a8532dae503
Step 16/17 : EXPOSE 8000
---> Using cache
---> c87fef4495a2
Step 17/17 : VOLUME ["/mattermost/data", "/mattermost/logs", "/mattermost/config", "/mattermost/plugins", "/mattermost/client/plugins"]
---> Using cache
---> e5125740fb5a
Successfully built e5125740fb5a
Successfully tagged mattermost-docker_app:latest

docker-compose run app -upgrade_db_30

Using existing config file /mattermost/config/config.json
Configure database connection...OK
Starting mattermost
Error: unknown shorthand flag: 'u' in -upgrade_db_30
Usage:
mattermost [flags]
mattermost [command]

Available Commands:
channel Management of channels
command Management of slash commands
config Configuration
export Export data from Mattermost
group Management of groups
help Help about any command
import Import data.
integrity Check database data integrity
jobserver Start the Mattermost job server
ldap LDAP related utilities
license Licensing commands
logs Display logs in a human-readable format
permissions Management of the Permissions system
plugin Management of plugins
reset Reset the database to initial state
roles Management of user roles
sampledata Generate sample data
server Run the Mattermost server
team Management of teams
user Management of users
version Display version information
webhook Management of webhooks

Flags:
-c, --config string Configuration file to use. (default "config.json")
--disableconfigwatch When set config.json will not be loaded from disk when the file is changed.
-h, --help help for mattermost

Use "mattermost [command] --help" for more information about a command.