I've upgraded to Greebo yesterday on my FreeBSD server through pkg (PHP 5.6, nginx 1.14) and since then in my browser I only see a blank page.
In the nginx error.log file I've found this, for example:
2018/04/28 09:44:34 [error] 2474#100162: *6403 FastCGI sent in stderr: "PHP message: PHP Fatal error: Call to undefined function json_encode() in /usr/local/www/dokuwiki/inc/template.php on line 343" while reading response header from upstream, client: xx.xx.xx.xx, server: ks3367031.kimsufi.com, request: "GET /doku.php?id=film_2015 HTTP/1.1", upstream: "fastcgi://unix:/var/run/php-fpm.sock:", host: "firminmaillard.org"
Does that say something to you? Shall I look somewhere else?
Thank you very much for your help,