issue62 readme updated with issue #62 (#73)

Author: echerniak

README.md

@@ -40,14 +40,19 @@ Prometheus exporter for IBM MQ, written in Java. Exposes API of IBM MQ and syste
        - [Channel status mapping](#channel-status-mapping)
        - [Listener status mapping](#listener-status-mapping)
 3. [Issues and Contributions](#issues-and-contributions)
-4. [Warning](#warning)
-5. [License](#license)
+4. [Known issues](#known-issues)
+5. [Warning](#warning)
+6. [License](#license)
 
 ## Getting Started
 
 #### Compatibility
 
-Support [IBM MQ](https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.0.0/com.ibm.mq.helphome.v90.doc/WelcomePagev9r0.htm) version 9.0.x.x.
+Supports IBM
+MQ(https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.0.0/com.ibm.mq.helphome.v90.doc/WelcomePagev9r0.htm)
+version 9.0.x.x and above. 
+
+Was tested on MQ ver.9.0.x.x and MQ ver. 9.1.x.x.
 
 #### Prerequisites
 - [IBM JRE 8 or higher](https://developer.ibm.com/javasdk/downloads/sdk8/) \ [Oracle JRE 8 or higher](https://www.oracle.com/technetwork/java/javase/downloads/index.html) \ [OpenJDK JRE 8 or higher](https://jdk.java.net/java-se-ri/8)
@@ -1186,6 +1191,21 @@ These metrics are collected via sending direct PCF commands to queue manager.
 Feel free to express your thoughts about the exporter, unexpected behaviour and\or issues. New feature suggestions are welcome, use [issue tracker](https://github.com/Cinimex-Informatica/mq-java-exporter/issues). 
 Pull requests are always welcome.
 
+## Known issues
+The following are known issues and may affect your use of exporter.
+
+* Metric mq_cpu_ram_total_estimate_megabytes may contain negative
+  values.
+  [#62](https://github.com/Cinimex-Informatica/mq-java-exporter/issues/62)
+  
+   This problem is related to this IBM
+   [APAR](https://www-01.ibm.com/support/docview.wss?uid=swg1IT24336).
+   The problem appeared during testing the exporter on MQ ver. 9.0.1.0.
+   We could not reproduce this problem on MQ ver. 9.1.0.1 (this version
+   includes fix for APAR above). Unfortunately, there is no way to fix
+   this problem on the exporter side and the only option is to wait for
+   the fix from IBM for MQ ver. 9.0.x.x.
+
 ## Warning
 The exporter is provided as-is with no guarantees.