This summary is not the rule. The rule text controls.
Here's a plain-English summary of this rule:
This rule explains who counts as a licensed attorney in Indiana. If you were properly admitted to practice law by an Indiana circuit court before July 1, 1931, and you're still in good standing, you're part of the state bar. The same goes for anyone admitted to practice law by the Indiana Supreme Court after that date, as long as they're also in good standing.
Basically, this rule sets the starting line for who is officially allowed to practice law in Indiana. It draws a line at 1931 because that's when the Indiana Supreme Court took over the job of admitting new attorneys, instead of leaving it to individual circuit courts. Anyone admitted before that date through the old system still counts, and so does everyone admitted the new way since then.
For regular people, this rule mostly matters behind the scenes. It helps explain why an attorney is considered licensed and part of the official bar, whether they were admitted decades ago under the old system or more recently under the current one.