Как исправить ошибку пхп связаную с разными версиями пхп в курсе codeigniter и в коде пхп 7.4.6?

A PHP Error was encountered
Severity: Notice

Message: Trying to access array offset on value of type null

Filename: controllers/News.php

Line Number: 68, 69, 70

Backtrace:

File: C:\xampp\htdocs\kinomonster\application\controllers\News.php
Line: 70
Function: _error_handler

File: C:\xampp\htdocs\kinomonster\index.php
Line: 315
Function: require_once

public function edit($slug = NULL) {
		$this->data['title'] = "редактировать новость";
		$this->data['news_item'] = $this->news_model->getNews($slug);

		/*if(empty($this->data['news_item'])) {
			show_404();
		}*/

		$this->data['title_news'] = $this->data['news_item']['title'];
		$this->data['content_news'] = $this->data['news_item']['text'];
		$this->data['slug_news'] = $this->data['news_item']['slug'];

		if($this->input->post('slug') && $this->input->post('title') && $this->input->post('text')) {
			$slug = $this->input->post('slug');
			$title = $this->input->post('title');
			$text = $this->input->post('text');

			if($this->news_model->updateNews($slug, $title, $text)) {
				echo "Новость успешно отредактирована";
			}
		}

		$this->load->view('templates/header', $this->data);
		$this->load->view('news/edit', $this->data);
		$this->load->view('templates/footer');

	}