Symfony 5: The Fast Track is the best book to learn
modern Symfony development, from zero to production. +300 pages in full color showing how to
combine Symfony with Docker, APIs, queues & async tasks, Webpack, Single-Page Applications, etc.
It won't be long before the release of symfony 1.1 and therefore continues the refactoring of its components. The logging system, the web debug toolbar and the symfony bootstraping have been refactored this week.
Symfony released 1.0.6 version this week and included the new CLI system with lots of improvements. Symfony 1.1 will also include a new form/validation/fillin layer that maintains compatibility with actual mechanism.