diff --git a/esbuild.config.mjs b/esbuild.config.mjs
index 8796b80..f685618 100644
--- a/esbuild.config.mjs
+++ b/esbuild.config.mjs
@@ -57,7 +57,7 @@ esbuild
     inject: ["./esbuild.injecthelper.mjs"],
     format: "cjs",
     // watch: !prod, // no longer valid in esbuild 0.17
-    target: "es2016",
+    target: "es2020",
     logLevel: "info",
     sourcemap: prod ? false : "inline",
     treeShaking: true,
diff --git a/pro/src/fsAzureBlobStorage.ts b/pro/src/fsAzureBlobStorage.ts
index 5f025b1..8d8ba7b 100644
--- a/pro/src/fsAzureBlobStorage.ts
+++ b/pro/src/fsAzureBlobStorage.ts
@@ -78,7 +78,7 @@ const fromBlobPropsToEntity = (
 
   let hash: undefined | string = undefined;
   if (props.contentMD5 !== undefined) {
-    hash = arrayBufferToHex(props.contentMD5.buffer);
+    hash = arrayBufferToHex(props.contentMD5.buffer as ArrayBuffer);
   }
 
   const entity: Entity = {
diff --git a/pro/src/fsOnedriveFull.ts b/pro/src/fsOnedriveFull.ts
index 63c9991..c1db031 100644
--- a/pro/src/fsOnedriveFull.ts
+++ b/pro/src/fsOnedriveFull.ts
@@ -575,7 +575,7 @@ export class FakeFsOnedriveFull extends FakeFs {
    */
   async _putUint8ArrayByRange(
     pathFragOrig: string,
-    payload: Uint8Array,
+    payload: Uint8Array<ArrayBuffer>,
     rangeStart: number,
     rangeEnd: number,
     size: number
diff --git a/src/encryptOpenSSL.ts b/src/encryptOpenSSL.ts
index 18a49a2..55f23db 100644
--- a/src/encryptOpenSSL.ts
+++ b/src/encryptOpenSSL.ts
@@ -24,7 +24,7 @@ const getKeyIVFromPassword = async (
   const k2 = await window.crypto.subtle.deriveBits(
     {
       name: "PBKDF2",
-      salt: salt,
+      salt: salt as Uint8Array<ArrayBuffer>,
       iterations: rounds,
       hash: "SHA-256",
     },
diff --git a/src/fsOnedrive.ts b/src/fsOnedrive.ts
index 06c56a7..240759d 100644
--- a/src/fsOnedrive.ts
+++ b/src/fsOnedrive.ts
@@ -729,7 +729,7 @@ export class FakeFsOnedrive extends FakeFs {
    */
   async _putUint8ArrayByRange(
     pathFragOrig: string,
-    payload: Uint8Array,
+    payload: Uint8Array<ArrayBuffer>,
     rangeStart: number,
     rangeEnd: number,
     size: number
diff --git a/src/misc.ts b/src/misc.ts
index 2d3b2ae..4e21266 100644
--- a/src/misc.ts
+++ b/src/misc.ts
@@ -88,9 +88,9 @@ export const mkdirpInVault = async (thePath: string, vault: Vault) => {
  * @returns ArrayBuffer
  */
 export const bufferToArrayBuffer = (
-  b: Buffer | Uint8Array | ArrayBufferView
+  b: Buffer | Uint8Array<ArrayBuffer> | ArrayBufferView
 ) => {
-  return b.buffer.slice(b.byteOffset, b.byteOffset + b.byteLength);
+  return b.buffer.slice(b.byteOffset, b.byteOffset + b.byteLength) as ArrayBuffer;
 };
 
 /**