diff --git a/package.json b/package.json
index ef7e444786..3b00189ad1 100644
--- a/package.json
+++ b/package.json
@@ -72,7 +72,7 @@
     "@types/json-stable-stringify": "^1.0.32",
     "@types/lodash.merge": "^4.6.6",
     "@types/long": "^4.0.0",
-    "@types/node": "14.0.13",
+    "@types/node": "^14.14.0",
     "@types/node-fetch": "^2.5.7",
     "@types/normalize-wheel": "^1.0.0",
     "@types/object.fromentries": "^2.0.0",
diff --git a/products/jbrowse-cli/README.md b/products/jbrowse-cli/README.md
index 75d74a621a..90f10a1996 100644
--- a/products/jbrowse-cli/README.md
+++ b/products/jbrowse-cli/README.md
@@ -518,6 +518,8 @@ OPTIONS
 
   --branch=branch     Download a development build from a named git branch
 
+  --clean             Removes old js,map,and LICENSE files in the installation
+
   --nightly           Download the latest development build from the main branch
 
 EXAMPLES
diff --git a/products/jbrowse-cli/src/base.ts b/products/jbrowse-cli/src/base.ts
index 51ca03bfe0..70c7a63e1e 100644
--- a/products/jbrowse-cli/src/base.ts
+++ b/products/jbrowse-cli/src/base.ts
@@ -291,7 +291,7 @@ export default abstract class JBrowseCommand extends Command {
       }
       return file
     }
-    return this.error(`Error: Could not find version: ${response.statusText}`, {
+    return this.error(`Could not find version: ${response.statusText}`, {
       exit: 90,
     })
   }
diff --git a/products/jbrowse-cli/src/commands/upgrade.ts b/products/jbrowse-cli/src/commands/upgrade.ts
index cc970a9155..7b84f12d44 100644
--- a/products/jbrowse-cli/src/commands/upgrade.ts
+++ b/products/jbrowse-cli/src/commands/upgrade.ts
@@ -5,6 +5,8 @@ import fetch from 'node-fetch'
 import unzip from 'unzipper'
 import JBrowseCommand from '../base'
 
+const { rm } = fs.promises
+
 export default class Upgrade extends JBrowseCommand {
   static description = 'Upgrades JBrowse 2 to latest version'
 
@@ -55,6 +57,9 @@ export default class Upgrade extends JBrowseCommand {
     nightly: flags.boolean({
       description: 'Download the latest development build from the main branch',
     }),
+    clean: flags.boolean({
+      description: 'Removes old js,map,and LICENSE files in the installation',
+    }),
     url: flags.string({
       char: 'u',
       description: 'A direct URL to a JBrowse 2 release',
@@ -64,13 +69,10 @@ export default class Upgrade extends JBrowseCommand {
   async run() {
     const { args: runArgs, flags: runFlags } = this.parse(Upgrade)
     const { localPath: argsPath } = runArgs as { localPath: string }
-
-    const { listVersions, tag, url, branch, nightly } = runFlags
+    const { clean, listVersions, tag, url, branch, nightly } = runFlags
 
     if (listVersions) {
-      const versions = (await this.fetchGithubVersions()).map(
-        version => version.tag_name,
-      )
+      const versions = (await this.fetchGithubVersions()).map(v => v.tag_name)
       this.log(`All JBrowse versions:\n${versions.join('\n')}`)
       this.exit()
     }
@@ -111,6 +113,14 @@ export default class Upgrade extends JBrowseCommand {
       )
     }
 
+    if (clean) {
+      this.log('Note: Clean requires node.js 14+')
+      await rm(path.join(argsPath, 'static'), { force: true, recursive: true })
+      const files = fs.readdirSync(argsPath)
+      files
+        .filter(f => f.includes('worker.js'))
+        .forEach(f => fs.unlinkSync(path.join(argsPath, f)))
+    }
     await response.body.pipe(unzip.Extract({ path: argsPath })).promise()
     this.log(`Unpacked ${locationUrl} at ${argsPath}`)
   }
diff --git a/yarn.lock b/yarn.lock
index f88cbf3dbc..ad02c7919c 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4755,12 +4755,7 @@
   resolved "https://registry.yarnpkg.com/@types/node/-/node-17.0.18.tgz#3b4fed5cfb58010e3a2be4b6e74615e4847f1074"
   integrity sha512-eKj4f/BsN/qcculZiRSujogjvp5O/k4lOW5m35NopjZM/QwLOR075a8pJW5hD+Rtdm2DaCVPENS6KtSQnUD6BA==
 
-"@types/node@14.0.13":
-  version "14.0.13"
-  resolved "https://registry.yarnpkg.com/@types/node/-/node-14.0.13.tgz#ee1128e881b874c371374c1f72201893616417c9"
-  integrity sha512-rouEWBImiRaSJsVA+ITTFM6ZxibuAlTuNOCyxVbwreu6k6+ujs7DfnU9o+PShFhET78pMBl3eH+AGSI5eOTkPA==
-
-"@types/node@^14.0.10", "@types/node@^14.6.2":
+"@types/node@^14.0.10", "@types/node@^14.14.0", "@types/node@^14.6.2":
   version "14.18.12"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-14.18.12.tgz#0d4557fd3b94497d793efd4e7d92df2f83b4ef24"
   integrity sha512-q4jlIR71hUpWTnGhXWcakgkZeHa3CCjcQcnuzU8M891BAWA2jHiziiWEPEkdS5pFsz7H9HJiy8BrK7tBRNrY7A==
@@ -7692,7 +7687,7 @@ clone@~0.1.9:
   resolved "https://registry.yarnpkg.com/clone/-/clone-0.1.19.tgz#613fb68639b26a494ac53253e15b1a6bd88ada85"
   integrity sha1-YT+2hjmyaklKxTJT4Vsaa9iK2oU=
 
-clsx@^1.0.0, clsx@^1.0.4, clsx@^1.1.0, clsx@^1.1.1:
+clsx@^1.0.4, clsx@^1.1.0, clsx@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/clsx/-/clsx-1.1.1.tgz#98b3134f9abbdf23b2663491ace13c5c03a73188"
   integrity sha512-6/bPho624p3S2pMyvP5kKBPXnI3ufHLObBFCfgx+LkeR5lg2XYy2hqZqUf45ypD8COn2bhgGJSUE+l5dhNBieA==