Every year Google has rolled out several Google Algorithmic Update. Some of the Google updates are major while some of the Google updates are minor.
Below are list of Google Algorithmic Update in 2015.
Panda 4.2, July 18, 2015
2-3% of queries were affected; confirmed, announced. Google says a Panda refresh began this weekend, but will take months to fully roll out.
The Quality Update - May 3, 2015
On 3rd May 2015 Google announce Phantom 2 update. Google says it is a Quality update and it had a broad impact but Google didn't reveal any specific nature about the update.
Mobile Update "Mobilegeddon" - April 21, 2015
For the first time Google has Pre-announced about the algorithmic update which will affect the major search rankings in Google and Google will prefer Mobile friendly sites for the ranking in search engines.
Read about Google Mobile Friendly Update.
Read about Google Mobile Friendly Update.
Unnamed Update - February 4, 2015
Many webmasters and SERP trackers found that there is major flux e-commerce site for the mobile usability. But Google didn't confirm an update.
Check out the list of Google Algorithmic Update in 2014.
Ref : https://moz.com/google-algorithm-change
Ref : https://moz.com/google-algorithm-change