We should all wait for the full financial Report instead of this short summary to conclude anything about the Future of Planet Zoo. What I can find is this sentence from Dorans link:
"Alongside these two new major game releases, Frontier's existing game portfolio is expected to continue to deliver substantial on-going revenue contributions in FY24, supported by new content."
FY 2024 goes until 31st of May 2024. Until then we potentially will get DLCs. Everything else (perhaps even a spring DLC) just is pure speculation. As I already said only the complete financial Report will enlighten us. What we know from the semi annual Report from November PZ still was sold Well after half of FY 2023 followed by a popular Grasslands animal Pack and a perhaps Not so popular Tropical Pack afterwards which complete this FY2023.