Removing footer credit for this specific theme
<p>I was wondering if after I purchased this theme I could remove the footer credit under a regular license for this theme?</p>

<p><a href="https://themes.getbootstrap.com/product/boomerang-bootstrap-4-business-corporate-theme/" rel="nofollow noreferrer">https://themes.getbootstrap.com/product/boomerang-bootstrap-4-business-corporate-theme/</a></p>

<p><strong>No.</strong> </p>

<p>Source: <a href="https://themes.getbootstrap.com/licenses/" rel="nofollow noreferrer">https://themes.getbootstrap.com/licenses/</a></p>

<p>What you are describing is a "derivative work", or in the parlance of the above link, a "derivative theme". No license offered by the vendor allows for derivative themes.</p>

licensing