detailed in <a href="/issue/61716">proposal #61716</a>. The most important changes are:
</p>

<ul>
<li>The <code>Read</code> method, deprecated in <code>math/rand</code>,
was not carried forward for <code>math/rand/v2</code>.
(It remains available in <code>math/rand</code>.)
The vast majority of calls to <code>Read</code> should use
<a href="/pkg/crypto/rand/#Read"><code>crypto/rand</code>’s <code>Read</code></a> instead.

<code>q = x / y</code> and remainder <code>r = x % y</code> satisfy the following
relationships:
</p>

<pre>
x = q*y + r  and  |r| &lt; |y|
</pre>

<p>
with <code>x / y</code> truncated towards zero
(<a href="https://en.wikipedia.org/wiki/Modulo_operation">"truncated division"</a>).
</p>

<pre>
 x     y     x / y     x % y
 5     3       1         2
-5     3      -1        -2

<code>q = x / y</code> and remainder <code>r = x % y</code> satisfy the following
relationships:
</p>

<pre>
x = q*y + r  and  |r| &lt; |y|
</pre>

<p>
with <code>x / y</code> truncated towards zero
(<a href="https://en.wikipedia.org/wiki/Modulo_operation">"truncated division"</a>).
</p>

<pre>
 x     y     x / y     x % y
 5     3       1         2
-5     3      -1        -2