We noticed a behavior with **formatGmt** function especially around using **YYYY** vs **yyyy**, anyone facing the same?

Below is showing one year ahead:

```
system.debug('GMT Time'+System.now().formatGmt('E, dd MMM YYYY HH:mm:ss z'));

```

The above code worked perfectly till last week, starting today or over the weekend above code started to return **2021** for **YYYY**, when we replaced **YYYY** to **yyyy** (ie below code) it's returning 2020 ie showing current year 

```
system.debug('GMT Time'+System.now().formatGmt('E, dd MMM yyyy HH:mm:ss z'));

```