EmonPi stopped updating remote EmonCMS after system upgrade

After upgrading both my local EmonPi and remote EmonCMS, all values handled by EmonPi/EmonHub stopped updating from EmonPi to the remote site. My hand-crafted scripts with JSON updates for other type of sensors still work fine. The error messages in emoncms.log are revealing enough, but the required action is not:

2018-11-03 12:47:11.684|ERROR|input_controller.php|{“success”: false, “message”: “Format error, json string supplied is not valid”} for User: 1

I have not touched the Emonhub configuration on the local EmonPi. Locally, everything works just as before. Obviously, something has changed with JSON updates, or the receiving end is expecting something else now; is there a way to monitor what the EmonPi sends to the remote site?

Server Information
Emoncms Version 9.9.3
Modules Lib : Modules : Theme : Administration : Dashboard v1.3.1 : docs : EventProcesses : Feed : Graph v1.2.1 : Input : CoreProcess : Schedule : scripts : Time : User : Visualisation
Git URL GitHub - emoncms/emoncms: Web-app for processing, logging and visualising energy, temperature and other environmental data
Git Branch * master
Server OS Linux 4.15.0-38-generic
Host meteo meteo.husa.fi (2a01:4f9:c010:2a68::1)
Date 2018-11-03 14:51:07 EET
Uptime 14:51:07 up 1 day, 4:24, 3 users, load average: 0.01, 0.00, 0.00
HTTP Server Apache/2.4.29 (Ubuntu) HTTP/1.1 CGI/1.1 443
MySQL Version 5.7.24-0ubuntu0.18.04.1
Host localhost (127.0.0.1)
Date 2018-11-03 14:51:07 (UTC 02:00‌​)
Stats Uptime: 102288 Threads: 1 Questions: 681987 Slow queries: 0 Opens: 211 Flush tables: 1 Open tables: 204 Queries per second avg: 6.667
Memory RAM Used: 20.96% Total: 1.9 GB Used: 407.76 MB Free: 1.5 GB
Swap Used: 0.00% Total: 135.6 MB Used: 0 B Free: 135.6 MB
Disk Mount Stats
/ Used: 17.26% Total: 18.72 GB Used: 3.23 GB Free: 14.68 GB
PHP Version 7.2.11-3+ubuntu18.04.1+deb.sury.org+1 (Zend Version 3.2.0)
Modules apache2handler : calendar v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : Core v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : ctype v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : curl v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : date v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : dom v20031129 : exif v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : fileinfo v1.0.5 : filter v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : ftp v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : gettext v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : hash v1.0 : iconv v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : json v1.6.0 : libxml v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : mbstring v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : mysqli v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : mysqlnd vmysqlnd 5.0.12-dev - 20150407 - $Id: 38fea24f2847fa7519001be390c98ae0acafe387 $ : openssl v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : pcre v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : PDO v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : pdo_mysql v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : Phar v2.0.2 : posix v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : readline v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : redis v4.1.1 : Reflection v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : session v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : shmop v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : SimpleXML v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : sockets v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : sodium v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : SPL v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : standard v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : sysvmsg v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : sysvsem v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : sysvshm v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : tokenizer v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : wddx v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : xml v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : xmlreader v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : xmlwriter v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : xsl v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : Zend OPcache v7.2.11-3+ubuntu18.04.1+deb.sury.org+1 : zlib v7.2.11-3+ubuntu18.04.1+deb.sury.org+1
Client Information
HTTP Browser Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36
Screen Resolution 1440 x 900
Window Size 1425 x 767

Again, resolved almost with no action. Replaced the emonhub.conf section on local EmonPi with the default configuration and changed the hostname. The offending line was:

    sendstatus = 1                  # Enable sending WAN IP to Emoncms.org MyIP > https://emoncms.org/myip/list

This was the only real change I made (I had sendstatus = 0). I wonder why this must be 1.

Thanks @luru for the heads up on sendstatus I will look into it.

A post was split to a new topic: emonPi inputs do not appear on emoncms.org