Open /administrator/index.php?option=com_postinstall
In box "Release news from the Joomla! Project" show Array

| Setting | Value | 
|---|---|
| PHP Built On | Linux joomla 3.13.0-153-generic #203-Ubuntu SMP Thu Jun 14 08:52:28 UTC 2018 x86_64 | 
| Database Type | mysql | 
| Database Version | 5.5.61-0ubuntu0.14.04.1 | 
| Database Collation | utf8_general_ci | 
| Database Connection Collation | utf8mb4_general_ci | 
| PHP Version | 5.5.9-1ubuntu4.25 | 
| Web Server | Apache | 
| WebServer to PHP Interface | apache2handler | 
| Joomla! Version | Joomla! 3.8.11 Stable [ Amani ] 31-July-2018 14:00 GMT | 
| Joomla! Platform Version | Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT | 
| User Agent | Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36 | 
| Labels | Added: 
? | ||
| Status | New | ⇒ | Discussion | 
| Category | ⇒ | com_postinstall | 
 
                 
                I noticed that it runs this latest version on a windows server with php 7 and the error does not occur. I think it might have something to do with the PHP version.
| Labels | Added: 
J3 Issue | ||
 
                I think it might have something to do with the PHP version.
I cannot confirm with
PHP Version | 5.5.38-nmm2
Database Version | 5.5.58-nmm1-log
Joomla! Version | Joomla! 3.8.11 Stable [ Amani ] 31-July-2018 14:00 GMT
| Status | Discussion | ⇒ | Information Required | 
| Closed_By | Quy | ⇒ | joomla-cms-bot | 
| Status | Information Required | ⇒ | Closed | 
| Closed_Date | 0000-00-00 00:00:00 | ⇒ | 2018-10-09 15:22:13 | 
| Closed_By | ⇒ | Quy | 
 
                Set to "closed" on behalf of @Quy by The JTracker Application at issues.joomla.org/joomla-cms/21594
 
                Unable to reproduce. This can be reopened when more information is provided.
can't confirm:
System information
CloudAccess.net