diff --git a/core/src/replay_stage.rs b/core/src/replay_stage.rs
index b14eaddcae..820bd6c1fc 100644
--- a/core/src/replay_stage.rs
+++ b/core/src/replay_stage.rs
@@ -1747,17 +1747,19 @@ impl ReplayStage {
 
     pub fn get_unlock_switch_vote_slot(operating_mode: OperatingMode) -> Slot {
         match operating_mode {
-            OperatingMode::Development => std::u64::MAX / 2,
+            OperatingMode::Development => 0,
             OperatingMode::Stable => std::u64::MAX / 2,
-            OperatingMode::Preview => std::u64::MAX / 2,
+            // Epoch 63
+            OperatingMode::Preview => 21_692_256,
         }
     }
 
     pub fn get_unlock_heaviest_subtree_fork_choice(operating_mode: OperatingMode) -> Slot {
         match operating_mode {
-            OperatingMode::Development => std::u64::MAX / 2,
+            OperatingMode::Development => 0,
             OperatingMode::Stable => std::u64::MAX / 2,
-            OperatingMode::Preview => std::u64::MAX / 2,
+            // Epoch 63
+            OperatingMode::Preview => 21_692_256,
         }
     }