INSTALL-WINDOWS-IIS.md has said MySQL 8.4 LTS is standard for new installs since
8.0 reached end of life in April 2026, while both compose files and the offline
bundler still pinned 8.0. A site reading the Windows runbook and a site reading
the Docker one were being told to run different servers, and the migration page
written this week sent people onto the dead one.
Verified against a real server rather than by editing a tag: 8.4.11, core chain
plus five plugin chains applied clean, 66 tables at a single utf8mb4_unicode_ci
collation, six alembic version tables. The image's PyMySQL authenticates against
8.4's caching_sha2_password, which is what requirements.in already pins
cryptography for.
Existing servers need one thing done FIRST: 8.4 removes mysql_native_password,
so an account created on 5.6 or 5.7 must be moved to caching_sha2_password
before the upgrade or it cannot authenticate afterwards. In-place also has no
downgrade path, and 5.7 cannot reach 8.4 in one hop. For databases this size a
dump into a fresh 8.4 server is the better trade: same outage, and the old
server stays as the rollback.
Air-gapped sites need a fresh offline bundle, because the tarball carries the
MySQL image alongside the app image.
Also here, found by having it bite during that verification: the db healthcheck
pinged over the unix socket, and the entrypoint's init pass answers on the
socket while running the server with --skip-networking. The probe therefore
reported healthy DURING init, which is what `depends_on: service_healthy` gates
api and migrate on. A ping passed at 8 seconds and the next query failed because
the server was mid-restart. Probing 127.0.0.1 keeps it red until the real server
is listening.
The pieces existed across three pages and nothing connected them, so "can we go
from IIS to Docker" had no answer to point at. It is a fair question with a
short answer: the application keeps state in exactly two places, the database
and the instance directory, and nothing is encrypted at rest with SECRET_KEY or
JWT_SECRET_KEY, so a move is a dump plus a directory copy. The schema is
identical across topologies.
What the page spends its length on is the part that is NOT the data, because
that is where the time goes. The server address is baked into things that are
not the server: GE-Enforce manifests, the generated collector script, the
printer client scripts, and printed QR codes, which cannot be swept at all.
Keeping the hostname and repointing DNS makes the migration invisible to the
fleet; changing it does not.
Three other traps, each of which has a symptom that shows up later rather than
at cutover: an aliased IIS site needs MOUNT_PATH and a dist built for that
subpath, while the image builds for the root; an older dump can carry latin1 or
3-byte utf8 table definitions that load quietly into a utf8mb4 server and only
misbehave on the first accented name; and a restored instance directory needs
chown, because docker cp writes under the copying user's uid and the container
runs as shopdb.
Covers both directions plus Docker to a new Docker host, and ends with a cutover
checklist that leaves the old stack stopped rather than removed until a bay has
checked in on a working day.
Also fixes two links in START-HERE that pointed at files which are not there:
the ADR index needed its adr/ prefix, and LLM-GUIDE.md is llms.txt.
