Steps to reproduce:

1. Configure to store history in elasticsearch (trends in MySQL)
2. Upgrade (install) to 4.0.7

Result:

mysql> select * from trends order by clock desc limit 1;

+--------+------------+-----+-----------+-----------+-----------+
| itemid | clock      | num | value_min | value_avg | value_max |
+--------+------------+-----+-----------+-----------+-----------+
|    818 | 1556593200 |  60 | 0.0062    | 0.0062    | 0.0062    |
+--------+------------+-----+-----------+-----------+-----------+

The day I upgraded server ^^^
Current timestamp:

$ date +%s
1556801027

Expected:
Zabbix writes trend values to MySQL.

We're using Zabbix + Elasticsearch since last summer everything with trends was fine (except zabbix web ui cannot show trends with ES enabled  See: https://support.zabbix.com/browse/ZBX-15160). We used Grafana to get trend values via Zabbix API. Upgraded server to fix memory leak (https://support.zabbix.com/browse/ZBX-15774) and no new trend values since upgrade. This issue could be related.

Server configuration:
LogFile=/var/log/zabbix/zabbix_server.log
LogFileSize=0
PidFile=/var/run/zabbix/zabbix_server.pid
SocketDir=/var/run/zabbix
DBHost=127.0.0.1
DBName=zabbix
DBUser=zabbix
DBPassword=***
DBPort=7001
HistoryStorageURL=http://localhost:9200HistoryStorageDateIndex=1
StartPollers=4
StartTrappers=2
SNMPTrapperFile=/var/log/snmptrap/snmptrap.log
MaxHousekeeperDelete=100000
CacheSize=2G
StartDBSyncers=16
HistoryCacheSize=2G
HistoryIndexCacheSize=256M
TrendCacheSize=128M
ValueCacheSize=6G
Timeout=5
AlertScriptsPath=/usr/lib/zabbix/alertscripts
ExternalScripts=/usr/lib/zabbix/externalscripts
FpingLocation=/usr/bin/fping
Fping6Location=/usr/bin/fping6
LogSlowQueries=5000
ProxyConfigFrequency=60