Here is what has changed
Title tags have been increased to 70–71 characters, which is up from its previous 50–60 characters. That’s at least enough to fit in another word or two.
Meta descriptions have been increased by 100 characters per line, and extended from two to three lines. That’s a significant increase, and presents far more of an opportunity to tell searchers what the page is about.
Google is still truncating the descriptions to two lines for many search results still, so you may still see them coming in at around 160 characters at times. When an three line snipped is display they come in at 278 characters per line.
It’s important to note that this may be a test which Google could reverse at any time. By the company’s own admission, it is always A/B testing. So it’s a good idea not to base your #SEO efforts on these numbers until it’s known for sure if the test will become a permanent change.