docs: mention poor compatibility with dnscrypt-proxy

Readme.md

@@ -67,6 +67,10 @@ docker run -d --name doh-server \
   satishweb/doh-server
 ```
 
+## Logging
+
+All log lines (by either doh-client or doh-server) are written into `stderr`; you can view them using your OS tool of choice (`journalctl` when using systemd).
+
 ## Server Configuration
 
 The following is a typical DNS-over-HTTPS architecture:
@@ -315,6 +319,10 @@ Currently supported features are:
 - [X] EDNS0 large UDP packet (4 KiB by default)
 - [X] EDNS0-Client-Subnet (/24 for IPv4, /56 for IPv6 by default)
 
+## Known issues
+
+* it does not work well with [dnscrypt-proxy](https://github.com/DNSCrypt/dnscrypt-proxy), you might want to use either (or fix the compatibility bugs by submitting PRs)
+
 ## The name of the project
 
 This project is named "DNS-over-HTTPS" because it was written before the IETF DoH project. Although this project is compatible with IETF DoH, the project is not affiliated with IETF.