activating the plugin all pages went empty

Assalamu ‘alaikum warahmatuLlahi wabarakatuh,
after activating and setting up the ‘Islamic Books by EDC’ plugin I noticed that the two test pages I had went empty.
When editing the pages I see the text in the editor; but after saving the pages and viewing them I get a page with the title of the page and the edit link.

I’m using wordpress 4.5.3 with php7.

Here is a piece of apache log:
[Sat Jul 30 19:09:07.386249 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP Warning: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead in /var/www/wordpress_local/wp-content/plugins/islamic-books/setting.php on line 212, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386399 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP Stack trace:, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386423 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 1. {main}() /var/www/wordpress_local/index.php:0, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386444 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 2. require() /var/www/wordpress_local/index.php:17, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386460 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 3. require_once() /var/www/wordpress_local/wp-blog-header.php:19, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386475 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 4. include() /var/www/wordpress_local/wp-includes/template-loader.php:75, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386491 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 5. get_template_part() /var/www/wordpress_local/wp-content/themes/twentysixteen/page.php:23, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386516 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 6. locate_template() /var/www/wordpress_local/wp-includes/general-template.php:167, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386555 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 7. load_template() /var/www/wordpress_local/wp-includes/template.php:531, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386568 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 8. require() /var/www/wordpress_local/wp-includes/template.php:574, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386583 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 9. the_content() /var/www/wordpress_local/wp-content/themes/twentysixteen/template-parts/content-page.php:20, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386596 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 10. apply_filters() /var/www/wordpress_local/wp-includes/post-template.php:240, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386610 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 11. EDC_books_replace() /var/www/wordpress_local/wp-includes/plugin.php:235, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
[Sat Jul 30 19:09:07.386624 2016] [:error] [pid 2714] [client 127.0.0.1:44559] PHP 12. preg_replace() /var/www/wordpress_local/wp-content/plugins/islamic-books/setting.php:212, referer: https://wordpress.local:18080/wp-admin/post.php?post=4&action=edit
Deactivating the plugin the pages showed correctly.

JazakumuLlahu khayran,

https://www.ads-software.com/plugins/islamic-books/