# Upstream baseline
The compatibility target is the `systemd-resolved` implementation in
`systemd/systemd` at commit:
```
de9dbc37ad4aa637e200ac02a0545095997055df
```
That snapshot is the official `v261` release. Compatibility work must be
compared against that exact tree before moving the baseline.
Primary reference surfaces:
- `src/resolve/`
- `man/systemd-resolved.service.xml`
- `man/org.freedesktop.resolve1.xml`
- `docs/WRITING_RESOLVER_CLIENTS.md`
- `docs/WRITING_NETWORK_CONFIGURATION_MANAGERS.md`
- `test/units/TEST-75-RESOLVED.sh`
- `test/units/TEST-89-RESOLVED-MDNS.sh`