My understanding of the specification is that a HistoricalDataNode can have a HA Configuration but it is not mandatory.

If the HA Configuration is not available I run into the following problem:

For ReadProcessed calculations the stepped property is needed because it has a direct impact on the calculation results.
Table 3 – HistoricalDataConfigurationType definition states:
"This Property also effects how some Aggregates are calculated. A value of True indicates the stepped interpolation mode. A value of False indicates SlopedInterpolation mode. The default value is False."

• Should that default be visible in some place in the servers address space? I could not find anything in the specification.
• How should the calculation work if the property is not there? Should the server just assume a default of false or return an error?
  Maybe the ServerCapabilities would be a good place to add a server default.