Update readme

Author: shulkaolka

README.md

@@ -108,6 +108,8 @@ The format of ``Start Polling From (optional)`` field should be like ``yyyy-mm-d
 - ``ss`` - second
 - ``sss`` - millisecond (optional)
 
+*Note:* please see [**Current-limitations**](#current-limitations).
+
 ### SELECT trigger (Deprecated)
 This action exists in JDBC component only for backward compatibility. New [**Select trigger**](#select-trigger) is recommended to use.
 
@@ -215,9 +217,7 @@ This action exists in JDBC component only for backward compatibility. [**Upsert
 - ``Oracle`` - compatible with Oracle Database 8.1.7 - 12.1.0.2
 - ``MSSQL`` - compatible with Microsoft SQL Server 2008 R2 and higher
 3. The current implementation of the action ``Upsert By Primary Key`` doesn't mark non-nullable fields as required fields at a dynamic metadata. In case of updating such fields with an empty value you will get SQL Exception ``Cannot insert the value NULL into...``. You should manually fill in all non-nullable fields with previous data, if you want to update part of columns in a row, even if data in that fields doesn't change. 
-
-## Known issues
-No known issues are there yet.
+4. **Get Rows Polling trigger** does not supported in Real-Time flows
 
 ## License
 Apache-2.0 © [elastic.io GmbH](https://www.elastic.io "elastic.io GmbH")