Plugin version 5.6 added new BBCode called Post Quote: [postquote]. It is a bit different from regular Quote and very useful if you work with the complex content that includes embedded elements from other websites or complex HTML that can’t be quoted without losing parts of the content.
So, with normal Quote, the Quote shortcode includes the whole content of the topic/reply, and it looks like this:
On the other hand, using Post Quote doesn’t include any actual content, just the reference to the topic or reply, like this:
In the end, both BBCodes will render in a similar way, but Post Quote will take the full content of the referenced post and render it. This will preserve everything in that post, including complex embedded stuff.
Post Quote is useful when user quotes the whole topic or reply. If the user selects one or two sentences from the content, then regular Quote BBCode still needs to be used. If you switch to Post Quote in the Quote settings, Post Quote will be used when the whole topic/reply is quoted, and Quote if the selection is quoted. To change which code is used, open plugin panel Modules -> Quotes -> BBCode to use.