Question about HP EliteDisplay E243i

According to HP product specifications: DisplayPort™ 1.2 (with HDCP support)

Even if such monitors exist, this one does not have a blue filter. However, this can also be solved on the operating system side. With Windows, this has been possible directly via the settings since the major update at the beginning of the year (2018) at the latest; with Mac OS, there are additional programmes such as f.lux that can filter the blue component.