diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3ccd54643..fe790e81ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -42,6 +42,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * (crypto/keyring) [#21653](https://github.com/cosmos/cosmos-sdk/pull/21653) New Linux-only backend that adds Linux kernel's `keyctl` support.
 
+### Improvements
+
+* (server) [#21941](https://github.com/cosmos/cosmos-sdk/pull/21941) Regenerate addrbook.json for in place testnet.
+
 ### Bug Fixes
 
 * (sims) [21906](https://github.com/cosmos/cosmos-sdk/pull/21906) Skip sims test when running dry on validators
diff --git a/server/start.go b/server/start.go
index 80e29b9c12..dbc5754646 100644
--- a/server/start.go
+++ b/server/start.go
@@ -7,6 +7,7 @@ import (
 	"io"
 	"net"
 	"os"
+	"path/filepath"
 	"runtime/pprof"
 	"strings"
 	"time"
@@ -749,6 +750,17 @@ func testnetify(ctx *Context, testnetAppCreator types.AppCreator, db dbm.DB, tra
 		return nil, err
 	}
 
+	// Regenerate addrbook.json to prevent peers on old network from causing error logs.
+	addrBookPath := filepath.Join(config.RootDir, "config", "addrbook.json")
+	if err := os.Remove(addrBookPath); err != nil && !os.IsNotExist(err) {
+		return nil, fmt.Errorf("failed to remove existing addrbook.json: %w", err)
+	}
+
+	emptyAddrBook := []byte("{}")
+	if err := os.WriteFile(addrBookPath, emptyAddrBook, 0o600); err != nil {
+		return nil, fmt.Errorf("failed to create empty addrbook.json: %w", err)
+	}
+
 	// Load the comet genesis doc provider.
 	genDocProvider := node.DefaultGenesisDocProviderFunc(config)