Changes are done in a soft way, to allow backward compatibility and don't stop working in all projects after an upgrade.
The most crucial change is report messages styles (this one is from summary type, short & condensed):
Here is a list of all the changes I made:
Change report messages (add emojis, text formatters, new data to summary),
Add logging levels (allow to change if we want a short report or get every test with error stack trace),
Add quiet mode (disable logging to terminal information about sending messages to slack during execution),
Little code refactor, move some code into separate modules,
Remove old & deprecated dependencies,
Create a separate config, which relays on the configuration in .testcaferc.json, after that on .env global variables and after that on default values,
Update generated tests (from scaffolded template of TestCafe reporter),
Update README about how it's looks like, installation, all configuration options & steps,
Update .travis.yml to build the library,
Refactor code consistency.