VESA Releases DisplayPort 2.1 Specification - DisplayPort
From a consumer's perspective, the physical standard hasn't changed—USB-C type 2.1 devices will plug into USB-C type 2.0 ports, and vice versa.
Conformance: requirements and recommendations - World Wide Web ...
WCAG 2.2 extends Web Content Accessibility Guidelines 2.1 [ WCAG21 ], which was published as a W3C Recommendation June 2018. Content that conforms to WCAG 2.2 also conforms to WCAG 2.0 and WCAG 2.1. The WG intends that for policies requiring conformance to WCAG 2.0 or WCAG 2.1, WCAG 2.2 can provide an alternate means of conformance.
HDMI 2.1: What you need to know - CNET
Illuminated speakers with 16.8 million RGB colors that react to the onscreen action and music. Deep, powerful bass emitted from a 6.5" subwoofer for impactful audio. Easily connect to PC, PlayStation, and Mac and more with USB, Bluetooth, optical, or 3.5mm Aux, and wired headset. Volume dial and multifunctional button for muting, BT pairing ...
Introduction to CSS 2.1 - World Wide Web Consortium (W3C)
In CSS 2.1, content may be generated by two mechanisms: The 'content' property, in conjunction with the :before and :after pseudo-elements. Elements with a value of 'list-item' for the 'display' property. 12.1 The :before and :after pseudo-elements.