At the top right hand side of the screen (see image below), you'll notice that there is a search bar known as "channel search".
The channel search functionality has been significantly improved in two key ways:
First, the channel search does exactly as the name would suggest. It helps you quickly find channels based on your search query. As per the example in the image above, the search was "J&B Smith" and it returned two results in which channels were named: "Smith vs. J&B" and "J&B, Smith, Williams & Co". You'll also notice that the channel search now support special characters that were not previously supported. An example of some special characters our clients often use include: (# & @ ! ? - + . ,)
Second, the channel search is now lightning fast. If you've used the search functionality before, you'll immediately notice a significant improvement in performance. It is important to note that the search is now limited to strictly channel names and does not include contacts or messages.