diff --git a/manifest.json b/manifest.json
index 7163f23f37..928a03dba4 100644
--- a/manifest.json
+++ b/manifest.json
@@ -2,7 +2,7 @@
   "manifest_version": 3,
   "name": "floccus bookmarks sync",
   "short_name": "floccus",
-  "version": "4.19.1",
+  "version": "5.0.0",
   "description": "__MSG_DescriptionExtension__",
   "icons": {
     "48": "icons/logo.png",
@@ -10,13 +10,6 @@
     "128": "icons/logo_128.png"
   },
 
-  "applications": {
-    "gecko": {
-      "id": "floccus@handmadeideas.org",
-      "strict_min_version": "57.0"
-    }
-  },
-
   "default_locale": "en",
 
   "permissions": ["alarms", "bookmarks", "storage", "unlimitedStorage", "tabs", "identity"],
@@ -42,6 +35,6 @@
   },
 
   "background": {
-    "scripts": ["dist/js/background-script.js"]
+    "service_worker": "dist/js/background-script.js"
   }
 }
diff --git a/package-lock.json b/package-lock.json
index 680609afe4..bde0b03a94 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -24,6 +24,7 @@
         "async-lock": "^1.2.8",
         "async-parallel": "^1.2.3",
         "batching-toposort": "^1.2.0",
+        "cheerio": "^1.0.0-rc.12",
         "cordova-plugin-device": "^2.1.0",
         "cordova-plugin-inappbrowser": "^5.0.0",
         "core-js": "3.x",
@@ -4188,8 +4189,7 @@
     "node_modules/boolbase": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/boolbase/-/boolbase-1.0.0.tgz",
-      "integrity": "sha512-JZOSA7Mo9sNGB8+UjSgzdLtokWAky1zbztM3WRLCbZ70/3cTANmQmOdR7y2g+J0e2WXywy1yS468tY+IruqEww==",
-      "dev": true
+      "integrity": "sha512-JZOSA7Mo9sNGB8+UjSgzdLtokWAky1zbztM3WRLCbZ70/3cTANmQmOdR7y2g+J0e2WXywy1yS468tY+IruqEww=="
     },
     "node_modules/boolean": {
       "version": "3.2.0",
@@ -4626,6 +4626,42 @@
         "node": "*"
       }
     },
+    "node_modules/cheerio": {
+      "version": "1.0.0-rc.12",
+      "resolved": "https://registry.npmjs.org/cheerio/-/cheerio-1.0.0-rc.12.tgz",
+      "integrity": "sha512-VqR8m68vM46BNnuZ5NtnGBKIE/DfN0cRIzg9n40EIq9NOv90ayxLBXA8fXC5gquFRGJSTRqBq25Jt2ECLR431Q==",
+      "dependencies": {
+        "cheerio-select": "^2.1.0",
+        "dom-serializer": "^2.0.0",
+        "domhandler": "^5.0.3",
+        "domutils": "^3.0.1",
+        "htmlparser2": "^8.0.1",
+        "parse5": "^7.0.0",
+        "parse5-htmlparser2-tree-adapter": "^7.0.0"
+      },
+      "engines": {
+        "node": ">= 6"
+      },
+      "funding": {
+        "url": "https://github.com/cheeriojs/cheerio?sponsor=1"
+      }
+    },
+    "node_modules/cheerio-select": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/cheerio-select/-/cheerio-select-2.1.0.tgz",
+      "integrity": "sha512-9v9kG0LvzrlcungtnJtpGNxY+fzECQKhK4EGJX2vByejiMX84MFNQw4UxPJl3bFbTMw+Dfs37XaIkCwTZfLh4g==",
+      "dependencies": {
+        "boolbase": "^1.0.0",
+        "css-select": "^5.1.0",
+        "css-what": "^6.1.0",
+        "domelementtype": "^2.3.0",
+        "domhandler": "^5.0.3",
+        "domutils": "^3.0.1"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/fb55"
+      }
+    },
     "node_modules/chokidar": {
       "version": "2.1.8",
       "resolved": "https://registry.npmjs.org/chokidar/-/chokidar-2.1.8.tgz",
@@ -5288,6 +5324,32 @@
       "integrity": "sha512-3wdGidZyq5PB084XLES5TpOSRA3wjXAlIWMhum2kRcv/41Sn2emQ0dycQW4uZXLejwKvg6EsvbdlVL+FYEct7A==",
       "dev": true
     },
+    "node_modules/css-select": {
+      "version": "5.1.0",
+      "resolved": "https://registry.npmjs.org/css-select/-/css-select-5.1.0.tgz",
+      "integrity": "sha512-nwoRF1rvRRnnCqqY7updORDsuqKzqYJ28+oSMaJMMgOauh3fvwHqMS7EZpIPqK8GL+g9mKxF1vP/ZjSeNjEVHg==",
+      "dependencies": {
+        "boolbase": "^1.0.0",
+        "css-what": "^6.1.0",
+        "domhandler": "^5.0.2",
+        "domutils": "^3.0.1",
+        "nth-check": "^2.0.1"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/fb55"
+      }
+    },
+    "node_modules/css-what": {
+      "version": "6.1.0",
+      "resolved": "https://registry.npmjs.org/css-what/-/css-what-6.1.0.tgz",
+      "integrity": "sha512-HTUrgRJ7r4dsZKU6GjmpfRK1O76h97Z8MfS1G0FozR+oF2kG6Vfe8JE6zwrkbxigziPHinCJ+gCPjA9EaBDtRw==",
+      "engines": {
+        "node": ">= 6"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/fb55"
+      }
+    },
     "node_modules/cssesc": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/cssesc/-/cssesc-3.0.0.tgz",
@@ -5595,6 +5657,19 @@
         "node": ">=6.0.0"
       }
     },
+    "node_modules/dom-serializer": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/dom-serializer/-/dom-serializer-2.0.0.tgz",
+      "integrity": "sha512-wIkAryiqt/nV5EQKqQpo3SToSOV9J0DnbJqwK7Wv/Trc92zIAYZ4FlMu+JPFW1DfGFt81ZTCGgDEabffXeLyJg==",
+      "dependencies": {
+        "domelementtype": "^2.3.0",
+        "domhandler": "^5.0.2",
+        "entities": "^4.2.0"
+      },
+      "funding": {
+        "url": "https://github.com/cheeriojs/dom-serializer?sponsor=1"
+      }
+    },
     "node_modules/domain-browser": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/domain-browser/-/domain-browser-1.2.0.tgz",
@@ -5605,6 +5680,44 @@
         "npm": ">=1.2"
       }
     },
+    "node_modules/domelementtype": {
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/domelementtype/-/domelementtype-2.3.0.tgz",
+      "integrity": "sha512-OLETBj6w0OsagBwdXnPdN0cnMfF9opN69co+7ZrbfPGrdpPVNBUj02spi6B1N7wChLQiPn4CSH/zJvXw56gmHw==",
+      "funding": [
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/fb55"
+        }
+      ]
+    },
+    "node_modules/domhandler": {
+      "version": "5.0.3",
+      "resolved": "https://registry.npmjs.org/domhandler/-/domhandler-5.0.3.tgz",
+      "integrity": "sha512-cgwlv/1iFQiFnU96XXgROh8xTeetsnJiDsTc7TYCLFd9+/WNkIqPTxiM/8pSd8VIrhXGTf1Ny1q1hquVqDJB5w==",
+      "dependencies": {
+        "domelementtype": "^2.3.0"
+      },
+      "engines": {
+        "node": ">= 4"
+      },
+      "funding": {
+        "url": "https://github.com/fb55/domhandler?sponsor=1"
+      }
+    },
+    "node_modules/domutils": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/domutils/-/domutils-3.1.0.tgz",
+      "integrity": "sha512-H78uMmQtI2AhgDJjWeQmHwJJ2bLPD3GMmO7Zja/ZZh84wkm+4ut+IUnUdRa8uCGX88DiVx1j6FRe1XfxEgjEZA==",
+      "dependencies": {
+        "dom-serializer": "^2.0.0",
+        "domelementtype": "^2.3.0",
+        "domhandler": "^5.0.3"
+      },
+      "funding": {
+        "url": "https://github.com/fb55/domutils?sponsor=1"
+      }
+    },
     "node_modules/duplexify": {
       "version": "3.7.1",
       "resolved": "https://registry.npmjs.org/duplexify/-/duplexify-3.7.1.tgz",
@@ -5737,6 +5850,17 @@
         "node": ">=8.6"
       }
     },
+    "node_modules/entities": {
+      "version": "4.5.0",
+      "resolved": "https://registry.npmjs.org/entities/-/entities-4.5.0.tgz",
+      "integrity": "sha512-V0hjH4dGPh9Ao5p0MoRY6BVqtwCjhz6vI5LT8AJ55H+4g9/4vbHx1I54fS0XuclLhDHArPQCiMjDxjaL8fPxhw==",
+      "engines": {
+        "node": ">=0.12"
+      },
+      "funding": {
+        "url": "https://github.com/fb55/entities?sponsor=1"
+      }
+    },
     "node_modules/env-paths": {
       "version": "2.2.1",
       "resolved": "https://registry.npmjs.org/env-paths/-/env-paths-2.2.1.tgz",
@@ -8391,6 +8515,24 @@
       "integrity": "sha512-mxIDAb9Lsm6DoOJ7xH+5+X4y1LU/4Hi50L9C5sIswK3JzULS4bwk1FvjdBgvYR4bzT4tuUQiC15FE2f5HbLvYw==",
       "dev": true
     },
+    "node_modules/htmlparser2": {
+      "version": "8.0.2",
+      "resolved": "https://registry.npmjs.org/htmlparser2/-/htmlparser2-8.0.2.tgz",
+      "integrity": "sha512-GYdjWKDkbRLkZ5geuHs5NY1puJ+PXwP7+fHPRz06Eirsb9ugf6d8kkXav6ADhcODhFFPMIXyxkxSuMf3D6NCFA==",
+      "funding": [
+        "https://github.com/fb55/htmlparser2?sponsor=1",
+        {
+          "type": "github",
+          "url": "https://github.com/sponsors/fb55"
+        }
+      ],
+      "dependencies": {
+        "domelementtype": "^2.3.0",
+        "domhandler": "^5.0.3",
+        "domutils": "^3.0.1",
+        "entities": "^4.4.0"
+      }
+    },
     "node_modules/http-cache-semantics": {
       "version": "4.1.1",
       "resolved": "https://registry.npmjs.org/http-cache-semantics/-/http-cache-semantics-4.1.1.tgz",
@@ -10982,7 +11124,6 @@
       "version": "2.1.1",
       "resolved": "https://registry.npmjs.org/nth-check/-/nth-check-2.1.1.tgz",
       "integrity": "sha512-lqjrjmaOoAnWfMmBPL+XNnynZh2+swxiX3WUE0s4yEHI6m+AwrK2UZOimIRl3X/4QctVqS8AiZjFqyOGrMXb/w==",
-      "dev": true,
       "dependencies": {
         "boolbase": "^1.0.0"
       },
@@ -11433,6 +11574,29 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/parse5": {
+      "version": "7.1.2",
+      "resolved": "https://registry.npmjs.org/parse5/-/parse5-7.1.2.tgz",
+      "integrity": "sha512-Czj1WaSVpaoj0wbhMzLmWD69anp2WH7FXMB9n1Sy8/ZFF9jolSQVMu1Ij5WIyGmcBmhk7EOndpO4mIpihVqAXw==",
+      "dependencies": {
+        "entities": "^4.4.0"
+      },
+      "funding": {
+        "url": "https://github.com/inikulin/parse5?sponsor=1"
+      }
+    },
+    "node_modules/parse5-htmlparser2-tree-adapter": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/parse5-htmlparser2-tree-adapter/-/parse5-htmlparser2-tree-adapter-7.0.0.tgz",
+      "integrity": "sha512-B77tOZrqqfUfnVcOrUvfdLbz4pu4RopLD/4vmu3HUPswwTA8OH0EMW9BlWR2B0RCoiZRAHEUu7IxeP1Pd1UU+g==",
+      "dependencies": {
+        "domhandler": "^5.0.2",
+        "parse5": "^7.0.0"
+      },
+      "funding": {
+        "url": "https://github.com/inikulin/parse5?sponsor=1"
+      }
+    },
     "node_modules/pascalcase": {
       "version": "0.1.1",
       "resolved": "https://registry.npmjs.org/pascalcase/-/pascalcase-0.1.1.tgz",
diff --git a/package.json b/package.json
index bce225cbfa..ea5fb9bc33 100644
--- a/package.json
+++ b/package.json
@@ -85,6 +85,7 @@
     "async-lock": "^1.2.8",
     "async-parallel": "^1.2.3",
     "batching-toposort": "^1.2.0",
+    "cheerio": "^1.0.0-rc.12",
     "cordova-plugin-device": "^2.1.0",
     "cordova-plugin-inappbrowser": "^5.0.0",
     "core-js": "3.x",
diff --git a/src/lib/adapters/WebDav.ts b/src/lib/adapters/WebDav.ts
index a891739968..3fa5d5f93f 100644
--- a/src/lib/adapters/WebDav.ts
+++ b/src/lib/adapters/WebDav.ts
@@ -465,7 +465,8 @@ function createXBEL(rootFolder, highestId) {
 
 function createHTML(rootFolder, highestId) {
   let output = `<!DOCTYPE NETSCAPE-Bookmark-file-1>
-<html>`
+<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=UTF-8">
+<TITLE>Bookmarks</TITLE>`
 
   output +=
     '<!--- highestId :' +
diff --git a/src/lib/serializers/Html.ts b/src/lib/serializers/Html.ts
index 081e7c881c..6991c01523 100644
--- a/src/lib/serializers/Html.ts
+++ b/src/lib/serializers/Html.ts
@@ -1,9 +1,10 @@
 import Serializer from '../interfaces/Serializer'
-import { Bookmark, Folder, ItemLocation } from '../Tree'
+import { Bookmark, Folder, ItemLocation, ItemType, TItem, TItemType } from '../Tree'
+import { load } from 'cheerio'
 
 class HtmlSerializer implements Serializer {
   serialize(folder) {
-    return `<DL><p>${this._serializeFolder(folder, '')}</p></DL>`
+    return `<DL><p>\n${this._serializeFolder(folder, '')}</DL><p>\n`
   }
 
   _serializeFolder(folder, indent) {
@@ -12,58 +13,112 @@ class HtmlSerializer implements Serializer {
         if (child instanceof Bookmark) {
           return (
             `${indent}<DT>` +
-            `<A HREF="${child.url}" TAGS="${''}" id="${child.id}">${child.title}</A>`
+            `<A HREF="${child.url}" TAGS="${''}" ID="${child.id}">${child.title}</A>\n`
           )
         } else if (child instanceof Folder) {
           const nextIndent = indent + '  '
           return (
-            `${indent}<DT><h3 id="${child.id}">${child.title}</h3>\n` +
-            `${indent}<DL><p>${this._serializeFolder(
+            `${indent}<DT><H3 ID="${child.id}">${child.title}</H3>\n` +
+            `${indent}<DL><p>\n${this._serializeFolder(
               child,
               nextIndent
-            )}</p></DL>`
+            )}${indent}</DL><p>\n`
           )
         }
       })
-      .join('\n')
+      .join('')
   }
 
   deserialize(html): Folder {
-    const parser = new DOMParser()
-    const document = parser.parseFromString(html, 'text/html')
-    const rootFolder = new Folder({id: '', title: '', location: ItemLocation.SERVER})
-    const dl = document.querySelector('dl')
-    const counter = {highestId: 1}
-    deserializeDL(dl, rootFolder, counter)
-    return rootFolder
+    const folders: Folder[] = parseByString(html)
+    if (folders.length === 1) {
+      folders[0].isRoot = true
+      return folders[0]
+    } else {
+      folders.forEach(f => f.parentId = '0')
+      return new Folder({id: '0', title: 'root', children: folders, location: ItemLocation.SERVER, isRoot: true})
+    }
   }
 }
 
-function deserializeDL(dl:Element, parentFolder:Folder, counter:{highestId: number}) {
-  for (let element:Element = dl.querySelector('dt'); element; element = element.nextElementSibling) {
-    const child = element.firstElementChild
-    if (child instanceof HTMLHeadingElement) {
-      const folder = new Folder({
-        parentId: parentFolder.id,
-        title: child.textContent,
-        id: child.id ? parseInt(child.id) : counter.highestId++,
-        location: ItemLocation.SERVER
-      })
-      parentFolder.children.push(folder)
-      if (child.nextElementSibling instanceof HTMLDListElement) {
-        const dl = child.nextElementSibling
-        deserializeDL(dl, folder, counter)
-      }
-    } else if (child instanceof HTMLAnchorElement) {
-      parentFolder.children.push(new Bookmark({
-        parentId: parentFolder.id,
-        url: child.href,
-        title: child.textContent,
-        id: child.id ? parseInt(child.id) : counter.highestId++,
-        location: ItemLocation.SERVER
-      }))
-    }
+export default new HtmlSerializer()
+
+// The following code is based on https://github.com/hold-baby/bookmark-file-parser
+// Copyright (c) 2019 hold-baby
+// MIT License
+
+export const getRootFolder = (body: cheerio.Cheerio) => {
+  const h3 = body.find('h3').first()
+
+  const isChrome = typeof h3.attr('personal_toolbar_folder') === 'string'
+
+  if (isChrome) {
+    return body.children('dl').first()
+  }
+
+  const isSafari = typeof h3.attr('folded') === 'string'
+
+  if (isSafari) {
+    return body
+  }
+
+  const isIE = typeof h3.attr('item_id') === 'string'
+
+  if (isIE) {
+    return body.children('dl').first()
   }
+
+  const isFireFox = h3.text() === 'Mozilla Firefox'
+
+  if (isFireFox) {
+    return body.children('dl').first()
+  }
+
+  return body.children('dl').first()
 }
 
-export default new HtmlSerializer()
+export const parseByString = (content: string) => {
+  const $ = load(content, {
+    decodeEntities: false
+  })
+
+  const body = $('body')
+  const root: Folder[] = []
+  const rdt = getRootFolder(body).children('dt')
+
+  const parseNode = (node: cheerio.Cheerio, parentId) => {
+    const eq0 = node.children().eq(0)
+    const title = eq0.html() || ''
+    let type: TItemType = ItemType.BOOKMARK
+    let url = ''
+    let id = eq0.attr('id') || ''
+    let children: TItem[] = []
+
+    switch (eq0[0].name) {
+      case 'h3':
+        // folder
+        const dl = node.children('dl').first()
+        const dts = dl.children()
+
+        const ls = dts.toArray().map((ele) => {
+          if (ele.name !== 'dt') return null
+          return parseNode($(ele), id)
+        })
+        children = ls.filter((item) => item !== null) as TItem[]
+        return new Folder({id, title, parentId, children, location: ItemLocation.SERVER})
+      case 'a':
+        // site
+        url = eq0.attr('href') || ''
+        return new Bookmark({id, title, url, parentId, location: ItemLocation.SERVER})
+    }
+    throw new Error('Failed to parse')
+  }
+
+  rdt.each((_, item) => {
+    const node = $(item)
+    const child = parseNode(node)
+    root.push(child)
+  })
+
+  return root
+}