I don’t have enough context from your message to determine which Prop 0 you’re referring to, and voting calendars vary by jurisdiction and ballot. If you can share the state or locality (and confirm which proposition number you mean), I can give a precise date and any relevant deadlines. In the meantime, here’s how to quickly find it:

• Check your state or county elections website for the current ballot measures and their vote dates.
• Look up “Prop 0” along with your state name in a trusted election information site to confirm the exact measure and its ballot date.
• If this is a California statewide measure, Proposition numbers and deadlines are typically listed on the California Secretary of State Elections page or your county elections office site.
• If you have a link or document for Prop 0, share it and I’ll extract the exact voting date and any registration or early-voting deadlines.