Upgrading from 4.x

5.0 adds 28 options and removes none, so existing command lines keep working. Six things do change, and the first three are the ones people notice:

	4.x	5.0	To keep the 4.x behaviour
Java	11	17	— (hard requirement)
What the listeners bind	every interface	127.0.0.1	--bind-address 0.0.0.0
Per-request logging	one INFO line per request	only failures and 5xx	--log-http url
Selenium relay logging	always logged	honours --log-http	--log-http forwarder:url
Docker image	—	sets TESTINGBOT_BIND_ADDRESS=0.0.0.0	— (published ports keep working)
Embedding the jar	Jetty 11 + Servlet API	Jetty 12 core handlers	— (source change)

Java 17. The jar's classes cannot be loaded by an older JVM. The tunnel checks the version itself and says so plainly, rather than failing as A JNI error has occurred.

Listeners bind loopback. In 4.x the Selenium relay (4445), the local proxy (8087), the insight endpoints (8003) and --web (8080) accepted connections from any machine that could route to yours. None of them authenticates: the relay attaches your TestingBot key and secret to everything it forwards, and the proxy will connect anywhere your machine can, including its own loopback. They now bind 127.0.0.1.

If your tests run on the same machine as the tunnel — the normal case — nothing changes. If they run elsewhere, add --bind-address 0.0.0.0 and restrict the port with a firewall. The Docker image sets that for you, because a loopback bind inside a container makes published ports unreachable; narrow it there on the host side of the publish instead (-p 127.0.0.1:4445:4445).

Quieter logs. 4.x logged a line for every proxied request. 5.0 logs failures and 5xx only. --log-http url restores a line per request, and --log-http takes a level per module — --log-http proxy:url,forwarder:none.