Pega 7.1.7 supports Application Based Validation in which when a rule is saved, the referencing rules are validated based on the application ruleset listings rather than the Ruleset pre-requisites.
Say a Ruleset belongs to two applications, and the ruleset of a rule that we are referencing is included in only one applicaiton, so when we save this rule which application gets validatd. and how does the other one get errors??
The following was found in Pega Developer Help for 7.1.7:
As a best practice for design, your unlocked ABV rulesets should belong to one Rule-Application (but can belong to more than one version). This prevents ABV rulesets from referring to rules that may not exist in all applications that the ruleset is contained in.
Alternately, rulesets should be refactored into applications that are included as built-on applications.
New rulesets should always employ ABV, unless refactoring does not work—in which case, the ruleset may be set to RSP.
Since you posted your question in the Senior System Architect course forum, I'm assuming your question is one of comparitive curiosity and not based on the course itself. Please note that the SSA 7 course exercise system is built on Pega 7.1.6, if you are preparing for the CSSA 7.1 exam that the current exam is based on Pega 7.1.6 information only. There will be no 7.1.7 based questions.