diff --git a/cabal.project b/cabal.project
index 33c782f5396..29fdcbeaf12 100644
--- a/cabal.project
+++ b/cabal.project
@@ -14,7 +14,7 @@ repository cardano-haskell-packages
 -- you need to run if you change them
 index-state:
   , hackage.haskell.org 2026-03-26T20:21:33Z
-  , cardano-haskell-packages 2026-04-14T21:25:56Z
+  , cardano-haskell-packages 2026-04-22T19:21:15Z
 
 active-repositories:
   , :rest
diff --git a/cardano-node-chairman/cardano-node-chairman.cabal b/cardano-node-chairman/cardano-node-chairman.cabal
index 2dd4258aca1..6d7927d1969 100644
--- a/cardano-node-chairman/cardano-node-chairman.cabal
+++ b/cardano-node-chairman/cardano-node-chairman.cabal
@@ -45,7 +45,7 @@ executable cardano-node-chairman
                       , cardano-crypto-class
                       , cardano-git-rev ^>= 0.2.2
                       , cardano-ledger-core
-                      , cardano-node ^>= 10.7
+                      , cardano-node ^>= 11.0
                       , cardano-prelude
                       , containers
                       , contra-tracer
diff --git a/cardano-node/cardano-node.cabal b/cardano-node/cardano-node.cabal
index 7742649365d..9f05daafaef 100644
--- a/cardano-node/cardano-node.cabal
+++ b/cardano-node/cardano-node.cabal
@@ -1,7 +1,7 @@
 cabal-version: 3.8
 
 name:                   cardano-node
-version:                10.7.1
+version:                11.0
 synopsis:               The cardano full node
 description:            The cardano full node.
 category:               Cardano,
@@ -149,7 +149,7 @@ library
                       , cardano-ledger-babbage
                       , cardano-ledger-binary >= 1.7.1
                       , cardano-ledger-byron
-                      , cardano-ledger-conway
+                      , cardano-ledger-conway >= 1.22.1.0
                       , cardano-ledger-core
                       , cardano-ledger-dijkstra
                       , cardano-ledger-shelley
diff --git a/cardano-node/src/Cardano/Node/Protocol/Cardano.hs b/cardano-node/src/Cardano/Node/Protocol/Cardano.hs
index 52cfbc4b954..09dd3b3088f 100644
--- a/cardano-node/src/Cardano/Node/Protocol/Cardano.hs
+++ b/cardano-node/src/Cardano/Node/Protocol/Cardano.hs
@@ -181,8 +181,8 @@ mkSomeConsensusProtocolCardano NodeByronProtocolConfiguration {
           shelleyBasedLeaderCredentials = shelleyLeaderCredentials
         }
       , Consensus.cardanoProtocolVersion = if npcExperimentalHardForksEnabled
-                                           then ProtVer (natVersion @11) 0
-                                           else ProtVer (natVersion @10) 8
+                                           then ProtVer (natVersion @12) 0
+                                           else ProtVer (natVersion @11) 0
         -- The remaining arguments specify the parameters needed to transition between two eras
       , Consensus.cardanoLedgerTransitionConfig =
           Ledger.mkLatestTransitionConfig
diff --git a/cardano-testnet/changelog.d/20260421_175934_jordan.millar_disable_experimental_hardforks_enabled.md b/cardano-testnet/changelog.d/20260421_175934_jordan.millar_disable_experimental_hardforks_enabled.md
new file mode 100644
index 00000000000..897c8a3a757
--- /dev/null
+++ b/cardano-testnet/changelog.d/20260421_175934_jordan.millar_disable_experimental_hardforks_enabled.md
@@ -0,0 +1,7 @@
+### Fixed
+
+- Disable `ExperimentalHardForksEnabled` in the default testnet config.
+  After the experimental-gated `cardanoProtocolVersion` was bumped to 12,
+  Conway-era testnets forged blocks with protocol version 12, which the Conway
+  BBody rule rejects (max protocol version = 11). Dropping the flag makes the
+  node use protocol version 11, which Conway accepts.
diff --git a/cardano-testnet/src/Testnet/Defaults.hs b/cardano-testnet/src/Testnet/Defaults.hs
index ef1976b7557..a88ddae2d58 100644
--- a/cardano-testnet/src/Testnet/Defaults.hs
+++ b/cardano-testnet/src/Testnet/Defaults.hs
@@ -219,9 +219,8 @@ defaultYamlHardforkViaConfig sbe =
   hardforkViaConfig :: ShelleyBasedEra era -> Aeson.KeyMap Aeson.Value
   hardforkViaConfig sbe' =
     Aeson.fromList $
-      [ ("ExperimentalHardForksEnabled", Aeson.Bool True)
-      , ("ExperimentalProtocolsEnabled", Aeson.Bool True) ]
-      ++ (case sbe' of
+      ("ExperimentalProtocolsEnabled", Aeson.Bool True)
+      : (case sbe' of
             ShelleyBasedEraShelley ->
                 [ ("TestShelleyHardForkAtEpoch", Aeson.Number 0) ]
             ShelleyBasedEraAllegra ->
diff --git a/cardano-testnet/test/cardano-testnet-golden/files/golden/node_default_config.json b/cardano-testnet/test/cardano-testnet-golden/files/golden/node_default_config.json
index cb0c0c45c86..47f505577f2 100644
--- a/cardano-testnet/test/cardano-testnet-golden/files/golden/node_default_config.json
+++ b/cardano-testnet/test/cardano-testnet-golden/files/golden/node_default_config.json
@@ -5,7 +5,6 @@
     "DijkstraGenesisFile": "dijkstra-genesis.json",
     "EnableLogMetrics": false,
     "EnableLogging": true,
-    "ExperimentalHardForksEnabled": true,
     "ExperimentalProtocolsEnabled": true,
     "LastKnownBlockVersion-Alt": 0,
     "LastKnownBlockVersion-Major": 9,
diff --git a/configuration/cardano/mainnet-config.json b/configuration/cardano/mainnet-config.json
index b587e72e99d..8f63b23fd06 100644
--- a/configuration/cardano/mainnet-config.json
+++ b/configuration/cardano/mainnet-config.json
@@ -18,7 +18,7 @@
     "SnapshotInterval": 4320
   },
   "MaxKnownMajorProtocolVersion": 2,
-  "MinNodeVersion": "10.7.0",
+  "MinNodeVersion": "11.0",
   "Protocol": "Cardano",
   "RequiresNetworkMagic": "RequiresNoMagic",
   "ShelleyGenesisFile": "mainnet-shelley-genesis.json",
diff --git a/configuration/cardano/mainnet-config.yaml b/configuration/cardano/mainnet-config.yaml
index f0d1cece56b..dbeb7c0944e 100644
--- a/configuration/cardano/mainnet-config.yaml
+++ b/configuration/cardano/mainnet-config.yaml
@@ -96,9 +96,9 @@ LedgerDB:
 
 ##### Version Information #####
 
-# Min is currently 10.7.0 due to change of config bundled peer-snapshot
+# Min is currently 11.0 due to change of config bundled peer-snapshot
 # version.
-MinNodeVersion: 10.7.0
+MinNodeVersion: "11.0"
 
 ##### Logging configuration #####
 
diff --git a/flake.lock b/flake.lock
index 3acaf16b533..550d7435e53 100644
--- a/flake.lock
+++ b/flake.lock
@@ -3,11 +3,11 @@
     "CHaP": {
       "flake": false,
       "locked": {
-        "lastModified": 1776203472,
-        "narHash": "sha256-husRfOULFemi5q+JpO7deykZxTKSIz0E4fCR387aO3Y=",
+        "lastModified": 1776891677,
+        "narHash": "sha256-QBhjAV4dwQG8TrSKQJuiBy55+iUXCrkQqhScj6pFU+Y=",
         "owner": "intersectmbo",
         "repo": "cardano-haskell-packages",
-        "rev": "3831817e4131b3ef5fe262e3f853b87bec8a24a0",
+        "rev": "c7fd8630157da3d91c13c13e6d54ed493830b914",
         "type": "github"
       },
       "original": {