After announcing our new seasonality update in November, we originally announced to include a soft reset of all ranks at the beginning of each season. However, many players expressed unhappiness with the weight these placement matches had on their overall season due to the amount of work they had put into grinding over the last few months to attain their rank. As a result we conducted our own research looking at various factors. Combining that with the 2018 season only lasting two months (as opposed to three for future seasons) we have decided to not perform a soft reset at the end of the December season and players will continue with their December rank into the first Season of 2019. Your 2018 Season IV rank will still be visible on your profile under the statistics tab.
We would love to hear your feedback and will be polling relevant topics for future seasons shortly.