Yes. Under PI 34, Life Licenses remain valid as long as the educator during the past five years has either been regularly employed by a school district or taken six semester credits. For more information, please see the guidance document at http://dpi.wi.gov/files/tepdl/pdf/Life-License-Guidance.pdf.
Invalid Life Licenses can be reactivated by completing six semester credits. If you just want to substitute teach, you can apply for a five-year substitute teacher license, which does not require any continuing professional development. Application directions are at http://tepdl.dpi.wi.gov/licensing/elo-initial-sub-wi-tips.