diff --git a/src/protocol/mod.rs b/src/protocol/mod.rs
index c806614529f4e902549e03aff14271826afe2623..44988824b0ca822a44d4640b61b480ee6eb19ba5 100644
--- a/src/protocol/mod.rs
+++ b/src/protocol/mod.rs
@@ -287,6 +287,7 @@ pub trait RunContext {
     fn did_put(&mut self, port: PortId) -> bool;
     fn get(&mut self, port: PortId) -> Option<ValueGroup>; // None if still waiting on message
     fn fires(&mut self, port: PortId) -> Option<Value>; // None if not yet branched
+    fn get_fork(&mut self) -> Option<bool>; // None if not yet forked
     fn get_channel(&mut self) -> Option<(Value, Value)>; // None if not yet prepared
 }
 
@@ -302,6 +303,7 @@ pub enum RunResult {
     BranchMissingPortState(PortId), // branch doesn't know about port firing
     BranchMissingPortValue(PortId), // branch hasn't received message on input port yet
     BranchAtSyncEnd,
+    BranchFork,
     BranchPut(PortId, ValueGroup),
 }
 
@@ -329,6 +331,8 @@ impl ComponentState {
                         return RR::NewComponent(definition_id, monomorph_idx, args),
                     EC::NewChannel =>
                         return RR::NewChannel,
+                    EC::NewFork =>
+                        return RR::BranchFork,
                     EC::BlockFires(port_id) => return RR::BranchMissingPortState(port_id),
                     EC::BlockGet(port_id) => return RR::BranchMissingPortValue(port_id),
                     EC::Put(port_id, value) => {
@@ -398,6 +402,7 @@ impl ComponentState {
                         // to the runtime
                         unreachable!();
                     },
+                    EvalContinuation::NewFork => unreachable!(),
                     // Outside synchronous blocks, no fires/get/put happens
                     EvalContinuation::BlockFires(_) => unreachable!(),
                     EvalContinuation::BlockGet(_) => unreachable!(),
@@ -431,6 +436,7 @@ impl ComponentState {
                     // Not possible to create component in sync block
                     EvalContinuation::NewComponent(_, _, _) => unreachable!(),
                     EvalContinuation::NewChannel => unreachable!(),
+                    EvalContinuation::NewFork => unreachable!(),
                     EvalContinuation::BlockFires(port) => {
                         return SyncBlocker::CouldntCheckFiring(port);
                     },
@@ -524,6 +530,11 @@ impl RunContext for EvalContext<'_> {
             EvalContext::Sync(_) => unreachable!(),
         }
     }
+
+    fn get_fork(&mut self) -> Option<bool> {
+        // Never actually used in the old runtime
+        return None;
+    }
 }
 
 // TODO: @remove once old runtime has disappeared