ROGERS, Circuit Judge. The First Step Act provision regarding retroactivity of the Fair Sentencing Act does not prohibit courts from considering a defendant’s post-sentencing conduct when deciding whether to reduce his sentence. As the Government concedes, the district court in this case erred in ruling that, in making such a determination under the First Step Act, the court could not consider post-sentencing conduct. A remand is accordingly required.

THAPAR, Circuit Judge. Forever is a really long time—no less so in tax law. The Internal Revenue Code requires that certain donations be “protected in perpetuity” for the donor to receive a tax deduction. I.R.C. § 170(h)(5)(A). The question here is whether a donation satisfies this requirement when it empowers the donor to make harmful changes to the donation whenever the donee fails to act within 45 days of the proposed change. The Tax Court found that this 45-day window falls well short of “perpetuity.” We agree and affirm.