The lazy loader has been updated to load visible elements more aggressively. In previous versions, the lazy loader would wait up to 3 seconds for the rest of the page to completely load before displaying embedded content. Starting with this update, visible (on-screen) elements are loaded immediately and will compete for resources with the rest of the page. This will prevent slow resources such as ads and large images from delaying embedded content.
The add-on's CSS has been updated to correctly handle long titles.
The oEmbed logic has been updated to limit the number of concurrent fetches to prevent resource exhaustion. The number of fetches is limited to 1 per page, with a maximum of 3 concurrent fetches across processes.

This is a recommended update if you use the click-to-load feature with oEmbed enabled.
Added a new option to replace the YouTube player with a lightweight placeholder. The placeholder is a single image with no text that loads and starts the YouTube player when clicked.

Updated Audiomack and Twitch. Note that the new Twitch embed only works on HTTPS sites that are served on port 443 at the moment. Hopefully Twitch will relax those restrictions.

Obsolete workarounds for the Vimeo and YouTube embeds have been removed.
This is the same workaround as this previous update.

If Vimeo videos don't load on Safari because of Domain Level Privacy, check the "Use the default Vimeo embed" option. Otherwise, don't.
This revision fixes a CSS injection issue in some of the templates.

The CSS issue was reported by ThemeHouse's Jake B.
Marketplace URLs are now ignored.
Some YouTube videos impose restrictions on which websites are allowed to embed them. This appears to be done by checking the content of the Referer header and/or accessing the iframe's parent. Because this add-on loads videos dynamically, some browsers such as Safari anonymize the origin of the request. In response, YouTube may refuse to serve the video and display a "Video unavailable" error instead. As a workaround, an option to use YouTube's default embed as been added. It will disable the lazy-loader and the miniplayer and it will allow YouTube to gather info about the parent webpage.

TL;DR: if YouTube videos don't load on Safari, check the "Use the default YouTube embed" option. Otherwise, don't.
This is a minor cosmetic update.