system/Pager/PagerRenderer.php
public function getNext()
	{
		if (! $this->hasNext())
		{
			return null;
		}

		$uri = clone $this->uri;

		if ($this->segment === 0)
		{
			$uri->addQuery('page', $this->last + 1);
		}
		else
		{
			$uri->setSegment($this->segment, $this->last + 1);
		}

		return (string) $uri;
	}
public function getNext()
	{
		if (! $this->hasNext())
		{
			return null;
		}

		$uri = clone $this->uri;

		if ($this->segment === 0)
		{
			$uri->addQuery('page', $this->last + 1);
		}
		else
		{
			$uri->setSegment($this->segment, $this->last + 1);
		}

		return (string) $uri;
	}
Returns a URL to the "next" page. The next page is NOT, the
page after the current page, but is the page that follows the
"last" page.

You MUST call hasNext() first, or this value may be invalid.

@return string|null