diff --git a/src/appchain.cairo b/src/appchain.cairo
index 5b97284..55e592a 100644
--- a/src/appchain.cairo
+++ b/src/appchain.cairo
@@ -5,6 +5,7 @@
 mod errors {
     const INVALID_ADDRESS: felt252 = 'Config: invalid address';
     const SNOS_INVALID_PROGRAM_OUTPUT_SIZE: felt252 = 'snos: invalid output size';
+    const SNOS_INVALID_CONFIG_HASH: felt252 = 'snos: invalid config hash';
     const SNOS_INVALID_MESSAGES_SEGMENTS: felt252 = 'snos: invalid messages segments';
 }
 
@@ -25,6 +26,7 @@ mod appchain {
         messaging_cpt, messaging_cpt::InternalTrait as MessagingInternal, IMessaging,
         output_process, output_process::{MessageToStarknet, MessageToAppchain},
     };
+    use piltover::snos_output::ProgramOutput;
     use piltover::snos_output;
     use piltover::state::component::state_cpt::HasComponent;
     use piltover::state::{state_cpt, state_cpt::InternalTrait as StateInternal, IState};
@@ -129,6 +131,15 @@ mod appchain {
                 errors::SNOS_INVALID_PROGRAM_OUTPUT_SIZE
             );
 
+            let mut program_output_mut = program_output;
+            let program_output_struct: ProgramOutput = Serde::deserialize(ref program_output_mut)
+                .unwrap();
+            let (_, current_config_hash): (felt252, felt252) = self.config.program_info.read();
+            assert(
+                program_output_struct.config_hash == current_config_hash,
+                errors::SNOS_INVALID_CONFIG_HASH
+            );
+
             let mut offset = snos_output::HEADER_SIZE;
 
             // TODO(#7): We should update SNOS output to have the messages count
diff --git a/src/config/component.cairo b/src/config/component.cairo
index c2471e8..5f04a95 100644
--- a/src/config/component.cairo
+++ b/src/config/component.cairo
@@ -20,7 +20,7 @@ mod config_cpt {
         interface::IOwnable,
     };
     use piltover::config::interface::IConfig;
-    use starknet::{ContractAddress, get_caller_address};
+    use starknet::ContractAddress;
     use super::errors;
 
     #[storage]
@@ -79,7 +79,7 @@ mod config_cpt {
             self
                 .emit(
                     ProgramInfoChanged {
-                        changed_by: get_caller_address(),
+                        changed_by: starknet::get_caller_address(),
                         old_program_hash: old_program_hash,
                         new_program_hash: program_hash,
                         old_config_hash: old_config_hash,
diff --git a/tests/test_appchain.cairo b/tests/test_appchain.cairo
index 677cccf..c30694a 100644
--- a/tests/test_appchain.cairo
+++ b/tests/test_appchain.cairo
@@ -136,6 +136,7 @@ fn update_state_ok() {
     );
 
     let imsg = IMessagingDispatcher { contract_address: appchain.contract_address };
+    let iconfig = IConfigDispatcher { contract_address: appchain.contract_address };
 
     let contract_sn = starknet::contract_address_const::<
         993696174272377493693496825928908586134624850969
@@ -156,6 +157,13 @@ fn update_state_ok() {
     ]
         .span();
 
+    snf::start_prank(CheatTarget::One(appchain.contract_address), c::OWNER());
+    iconfig
+        .set_program_info(
+            program_hash: 0x11,
+            config_hash: 2590421891839256512113614983194993186457498815986333310670788206383913888162
+        );
+
     // The state update contains a message to appchain, therefore, before
     // being sealed, it must be sent first.
     // The nonce must be adjusted to ensure the correct message to be sent.