1. Your understanding is correct as long as the runtime context has visibility to version 01-01-05.

2. If the rule in version 01-01-04 is Blocked and there is no rule in 01-01-05, then the blocked rule gets picked during rule resolution but you will get an exception. If there is a rule in 01-01-05 that is marked as available and your runtime context has visibility to 01-01-05, then that rule gets executed.

3. If the rule in 01-01-05 is marked available and your runtime context has visibility to version 01-01-05, then that rule gets executed. The "not available" rule is just removed from the candidates list during the rule resolution process. It is the same as the rule not present in the rulebase.

So, to your actual question about the difference between withdrawn and blocked. Just modifying your example a bit.

Suppose you have the following rules and your runtime context has visibility to version 01-01-05.

ABC-HR-Work-Request 01-01-04 Withdrawn ABC-HR-Work-Request 01-01-03 Available ABC-HR-Work-Request 01-01-02 Available ABC-HR-Work 01-01-03 Available

Then the rule in ABC-HR-Work 01-01-03 will get picked (ignoring the lower version rules in ABC-HR-Work-Request in the same ruleset).

Likewise, if you have the following rules,

ABC-HR-Work-Request 01-01-04 Blocked ABC-HR-Work-Request 01-01-03    Available

ABC-HR-Work-Request    01-01-02    Available

ABC-HR-Work   01-01-03 Available

Then the rule in ABC-HR-Work-Request 01-01-04 will get picked during rule resolution, but you will get an exception.