§ 906.Review By Reviewing Court Upon Appeal Taken Pursuant to Sections 904.1 and 904.2

Once an appeal is properly taken under § 904.1 or § 904.2, this section defines how far the reviewing court's authority extends. It isn't limited to the judgment or order named in the notice of appeal — the reviewing court may also review the verdict or decision and any intermediate ruling, proceeding, order, or decision that involves the merits, necessarily affects the judgment or order appealed from, or substantially affects a party's rights, including a new-trial ruling on an appeal from the judgment itself. Armed with that scope, the reviewing court may affirm, reverse, or modify the judgment or order, direct entry of the proper judgment or order, and order a new trial or further proceedings if necessary or proper.

The section also gives the respondent — the party who won below and had no need to appeal — a tool for defending that judgment. Without filing an appeal, the respondent may ask the reviewing court to review those same categories of rulings, not to seek reversal, but to test whether any error the appellant relies on prejudiced the appellant. That lets a respondent point to other rulings in the case to argue that any error was harmless.

The final sentence draws a boundary that matters as much as the grant of authority itself: this section doesn't let the reviewing court review any decision or order from which an appeal might have been taken. A ruling that was independently appealable — say, an injunction order under § 904.1(a)(6) — has to be appealed on its own timeline; a party can't skip that appeal and then smuggle a challenge to it into a later appeal from the final judgment.