I'd like to embed twitter widget which will contain search results with both hashtag and user account. '#hashtag OR @username' doesn't work
Whilst simple embeds can be simply constructed here, it seems that creating more complex search queries requires the new Search API (subject to the new freemium pricing tiers), though you'll need to render / format the response yourself.
On July 27, 2018, timeline widgets that rely on account-specific widget settings will no longer be rendered. From that time, all settings will be in the embed code itself as
data-*
attributes in the markup. We expect timelines to work as expected for the majority of users. Settings previously customised (for example link color and height), will not be applied. The content of the timelines - the Tweets - will be rendered in the same way.The one notable exception will be search timelines, which will no longer be rendered in the same way, and will fall back to a simple link that points to the corresponding search results on twitter.com.
We hope that your search timeline can be replaced with a user timeline, list timeline, collection timeline, or likes timeline which will offer more fine-grained control over what Tweets show up on your webpage.
We also continue to offer three tiers of the RESTful Search API which can help you transition from the search timeline if you are open to writing your own display code.
(emphasis added)
The new documentation is: https://dev.twitter.com/docs/embedded-timelines under the heading 'Search and #hashtag'.
Create a timeline here: https://twitter.com/settings/widgets/new/search.
I've had success with: #hashtag AND from:@user1 OR from:@user2
.