I recommend that for yoga history and philosophy you should read the following books: ‘The Yoga Tradition of the Mysore Palace’, ‘Yoga Touchstone’, ‘Dead Birds’ and ‘Yogasutracintamani’ by Dr N. Sjoman (can be ordered form this website via the contact page), ‘Yoga Body’ by Mark Singleton and ‘The Path of Modern Yoga’ by Elliott Goldberg (available from book shops and online suppliers).
The most significant recent development is the online availability of classes. Due to coronavirus yoga studios and fitness centres are shut, we are all compelled to practice more at home. The online classes are working surprisingly well, many people find it easier than driving to a studio, finding parking, etc. The online class also allows the individual to control their visibility and audibility, which is not possible in a class environment. The intention is to develop the online facilities further.
If you are looking for more specific guidance on reliable yoga resources, contact me through the contact page.