diff --git a/package-lock.json b/package-lock.json
index 3af4353..03f1cf4 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "mnemonist",
-  "version": "0.39.8",
+  "version": "0.40.0-rc1",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "mnemonist",
-      "version": "0.39.8",
+      "version": "0.40.0-rc1",
       "license": "MIT",
       "dependencies": {
         "obliterator": "^2.0.4"
diff --git a/package.json b/package.json
index 3429787..f9d66e6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mnemonist",
-  "version": "0.39.8",
+  "version": "0.40.0-rc1",
   "description": "Curated collection of data structures for the JavaScript/TypeScript.",
   "scripts": {
     "lint": "eslint --cache --ext .js,.mjs ./*.js ./*.mjs ./utils ./test",
diff --git a/test/exports/package-lock.json b/test/exports/package-lock.json
index 7f581a8..6256241 100644
--- a/test/exports/package-lock.json
+++ b/test/exports/package-lock.json
@@ -15,8 +15,7 @@
       }
     },
     "../..": {
-      "name": "mnemonist",
-      "version": "0.39.7",
+      "version": "0.40.0-rc1",
       "license": "MIT",
       "dependencies": {
         "obliterator": "^2.0.4"