Encoding problem after upgrade to Elastic 2.3

We faced encoding problem after upgrading Elastic from 2.1.1 to 2.3.0 and logstash from 2.1.1 to 2.3.0

Elastic server configuration:

Elastic 2.3.0
Logstash 2.3.0
Java 8 update 77
Windows server 2012 R2

We use Logstash for log parsing and loading them in Elastic.
There are cyrillic symbols in logs and they turned into questions ????? (in Elastic) after upgrade.
Logs encoding is Cyrrilic Windows 1251 (CP1251)

Were there some changes in encoding settings in Elastic/Logstash (in 2.3.0 releases)?

I'm not aware of problems, but try LS 2.3.1 as 2.3.0 had some issues.

Upgrade to LS 2.3.1 helped