Other Compatibility Issues

ContentFilteredTopics

• Starting with 5.1.0, Connext DDS includes a change in the generated typecode name when rtiddsgen’s -package option is used in Java. This change introduces the following backward-compatibility issue.

DataWriters in 4.5x and below will not be able to perform writer-side filtering for Connext DDS 5.1.0 DataReaders using ContentFilteredTopics. You will get a ContentFilteredTopic (CFT) compilation error message on the DataWriter side. Notice that this compatibility issue does not affect correctness, as the filtering will be done on the DataReader side.

Built-in Topics

Due to the addition of new values in the enumeration DDS::ServiceQosPolicyKind under DDS::ServiceQosPolicy, Connext DDS 5.1.0 or lower applications will not be able to get information about DataWriters and DataReaders created by Connext DDS 5.2.0 or higher Infrastructure Services by reading from the Publication and Subscription built-in topic DataReaders.

These infrastructure services are affected:

• RTI Routing Service
• RTI Recording Service (Record and Replay tools)
• RTI Database Integration Service (formerly, RTI Real-Time Connect)
• RTI Queuing Service

The 5.1.0 applications monitoring the built-in topics will print the following error message:

DDS_ServiceQosPolicy_from_presentation_service_kind:ERROR: 
  Failed to get service (unknown kind)
DDS_SubscriptionBuiltinTopicDataTransform:ERROR: 
  Failed to get service
PRESCstReaderCollator_addSample:!transform

Notice that this compatibility issue does not affect matching between the 5.1.0 DataReaders/DataWriters and the corresponding 5.2.0 Infrastructure Service DataReader/DataWriters. Within the middleware, discovery will still occur and these entities will communicate with each other.

Some Monitoring Types are not Backwards Compatible

Due to the way in which the type-assignability algorithm handled enumerations in Connext DDS 5.1.0, some of the monitoring types are not compatible with newer versions of the types. This means Connext DDS 5.1.0 applications using the monitoring library may fail to match with the newer versions of the monitoring types. Newer versions of the monitoring library, however, will match with older versions of the monitoring types because of updates that have been made to the type assignability algorithm.

The only incompatibility as of the release of 5.2.0 is with the DataReaderDescription and DataWriterDescription monitoring types. Monitoring applications built with 5.1.0 will not be able to subscribe to the DataReaderDescription and DataWriterDescription topics published by applications that are using version 5.2.0 and later.

[RTI Issue ID MONITOR-188]

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