diff --git a/lib/api-functions.ts b/lib/api-functions.ts
index eeeb2a2..63927cf 100644
--- a/lib/api-functions.ts
+++ b/lib/api-functions.ts
@@ -94,7 +94,7 @@ export async function connectionRequest(
       else if (name === "password") return password;
 
       const p = device[name];
-      if (p && p.value) return p.value[0];
+      if (p?.value) return p.value[0];
     } else if (exp[0] === "FUNC") {
       if (exp[1] === "REMOTE_ADDRESS") return remoteAddress;
       else if (exp[1] === "USERNAME") return username;
@@ -317,7 +317,7 @@ function sanitizeTask(task): void {
 
 export async function insertTasks(tasks: any[]): Promise<Task[]> {
   if (tasks && !Array.isArray(tasks)) tasks = [tasks];
-  else if (!tasks || tasks.length === 0) return tasks || [];
+  else if (!tasks?.length) return tasks || [];
 
   for (const task of tasks) {
     sanitizeTask(task);
diff --git a/lib/cache.ts b/lib/cache.ts
index feb0254..2bc539c 100644
--- a/lib/cache.ts
+++ b/lib/cache.ts
@@ -59,7 +59,7 @@ export async function set(
 
 export async function pop(key: string): Promise<any> {
   const res = await cacheCollection.findOneAndDelete({ _id: key });
-  if (res && res["value"]) return res["value"]["value"];
+  if (res?.["value"]) return res["value"]["value"];
   return null;
 }
 
diff --git a/lib/cwmp.ts b/lib/cwmp.ts
index d1b9fb6..5cc5d2c 100644
--- a/lib/cwmp.ts
+++ b/lib/cwmp.ts
@@ -93,7 +93,7 @@ async function authenticate(
     }
   }
 
-  if (authentication && authentication.method === "Digest") {
+  if (authentication?.method === "Digest") {
     const sessionNonce = sessionsNonces.get(sessionContext.httpRequest.socket);
 
     if (
@@ -434,7 +434,7 @@ async function applyPresets(sessionContext: SessionContext): Promise<void> {
   const deviceEvents = {};
   for (const p of deviceData.paths.find(Path.parse("Events.*"), false, true)) {
     const attrs = deviceData.attributes.get(p);
-    if (attrs && attrs.value && attrs.value[1][0] >= sessionContext.timestamp)
+    if (attrs?.value && attrs.value[1][0] >= sessionContext.timestamp)
       deviceEvents[p.segments[1] as string] = true;
   }
 
@@ -458,7 +458,7 @@ async function applyPresets(sessionContext: SessionContext): Promise<void> {
 
     if (!eventsMatch) continue;
 
-    if (preset.schedule && preset.schedule.schedule) {
+    if (preset.schedule?.schedule) {
       const r = scheduling.cron(
         sessionContext.timestamp,
         preset.schedule.schedule
@@ -786,7 +786,7 @@ async function endSession(sessionContext: SessionContext): Promise<void> {
     }
   }
 
-  if (sessionContext.doneTasks && sessionContext.doneTasks.length) {
+  if (sessionContext.doneTasks?.length) {
     saveCache = true;
     promises.push(
       db.clearTasks(sessionContext.deviceId, sessionContext.doneTasks)
@@ -1082,7 +1082,7 @@ async function processRequest(
   }
 
   if (sessionContext.state === 0) {
-    if (!rpc.cpeRequest || rpc.cpeRequest.name !== "Inform")
+    if (rpc.cpeRequest?.name !== "Inform")
       return reportBadState(sessionContext);
 
     const res = await inform(sessionContext, rpc);
@@ -1549,7 +1549,7 @@ async function listenerAsync(
   if (sessionContext)
     return processRequest(sessionContext, rpc, parseWarnings, bodyStr);
 
-  if (!(rpc.cpeRequest && rpc.cpeRequest.name === "Inform")) {
+  if (rpc.cpeRequest?.name !== "Inform") {
     logger.accessError({
       message: "Invalid session",
       sessionContext: {
diff --git a/lib/db.ts b/lib/db.ts
index 71ece72..52d1419 100644
--- a/lib/db.ts
+++ b/lib/db.ts
@@ -505,7 +505,7 @@ export async function saveDevice(
 
                 break;
               case "object":
-                if (!diff[1] || !diff[1].object || object2 !== object1) {
+                if (!diff[1]?.object || object2 !== object1) {
                   update["$set"][
                     path.length ? path.toString() + "._object" : "_object"
                   ] = !!object2;
@@ -513,7 +513,7 @@ export async function saveDevice(
 
                 break;
               case "writable":
-                if (!diff[1] || !diff[1].writable || writable2 !== writable1) {
+                if (!diff[1]?.writable || writable2 !== writable1) {
                   update["$set"][
                     path.length ? path.toString() + "._writable" : "_writable"
                   ] = !!writable2;
@@ -566,7 +566,7 @@ export async function saveDevice(
           for (const attrName of Object.keys(diff[1])) {
             if (
               diff[1][attrName][1] != null &&
-              (!diff[2] || !diff[2][attrName] || diff[2][attrName][1] == null)
+              diff[2]?.[attrName]?.[1] == null
             ) {
               const p = path.length ? path.toString() + "." : "";
               update["$unset"][`${p}_${attrName}`] = 1;
diff --git a/lib/device.ts b/lib/device.ts
index ee94642..96ca975 100644
--- a/lib/device.ts
+++ b/lib/device.ts
@@ -208,7 +208,7 @@ export function clear(
   timestamp = timestamp || 0;
 
   let descendantsTimestamp = timestamp;
-  if (attributes && attributes.object) {
+  if (attributes?.object) {
     if (attributes.object > descendantsTimestamp)
       descendantsTimestamp = attributes.object;
     if (!(attributes.object <= attributes.value))
diff --git a/lib/local-cache.ts b/lib/local-cache.ts
index 66b1612..386871a 100644
--- a/lib/local-cache.ts
+++ b/lib/local-cache.ts
@@ -131,7 +131,7 @@ async function fetchPresets(): Promise<Preset[]> {
 
     // If no keys are defined, consider all parameters as keys to keep the
     // same behavior from v1.0
-    if (!obj["_keys"] || !obj["_keys"].length)
+    if (!obj["_keys"]?.length)
       obj["_keys"] = Object.keys(obj).filter((k) => !k.startsWith("_"));
 
     return obj;
@@ -499,7 +499,7 @@ export function getConfig(
   if (!(key in snapshot.config)) {
     if (key in oldOpts) {
       let id;
-      if (context && context["id"]) {
+      if (context?.["id"]) {
         id = context["id"];
       } else if (cb) {
         id = cb(["PARAM", "DeviceID.ID"]);
diff --git a/lib/session.ts b/lib/session.ts
index ebbd4ba..8c5d756 100644
--- a/lib/session.ts
+++ b/lib/session.ts
@@ -136,7 +136,7 @@ export function configContextCallback(
     const path = paths.get(Path.parse(name));
     if (path) {
       const attrs = deviceData.attributes.get(path, 1);
-      if (attrs && attrs.value && attrs.value[1]) return attrs.value[1][0];
+      if (attrs?.value?.[1]) return attrs.value[1][0];
     }
   } else if (exp[0] === "FUNC") {
     if (exp[1] === "REMOTE_ADDRESS")
@@ -299,7 +299,7 @@ export async function transferComplete(
   if (!sessionContext.operationsTouched) sessionContext.operationsTouched = {};
   sessionContext.operationsTouched[commandKey] = 1;
 
-  if (rpcReq.faultStruct && rpcReq.faultStruct.faultCode !== "0") {
+  if (rpcReq.faultStruct?.faultCode !== "0") {
     revertDownloadParameters(sessionContext, operation.args.instance);
 
     const fault: Fault = {
@@ -418,13 +418,7 @@ function revertDownloadParameters(
   );
 
   const toClear = device.set(sessionContext.deviceData, p, timestamp, {
-    value: [
-      timestamp,
-      [
-        lastDownload && lastDownload.value[1] ? lastDownload.value[1][0] : 0,
-        "xsd:dateTime",
-      ],
-    ],
+    value: [timestamp, [lastDownload?.value[1]?.[0] || 0, "xsd:dateTime"]],
   });
 
   if (toClear) {
@@ -1041,7 +1035,7 @@ export async function rpcRequest(
   if (
     !sessionContext.virtualParameters.length &&
     !sessionContext.declarations.length &&
-    !(_declarations && _declarations.length) &&
+    !_declarations?.length &&
     !sessionContext.provisions.length
   )
     return { fault: null, rpcId: null, rpc: null };
@@ -1116,7 +1110,7 @@ export async function rpcRequest(
     return rpcRequest(sessionContext, _declarations);
   }
 
-  if (_declarations && _declarations.length) {
+  if (_declarations?.length) {
     delete sessionContext.syncState;
     if (!sessionContext.declarations[0]) sessionContext.declarations[0] = [];
     sessionContext.declarations[0] = sessionContext.declarations[0].concat(
@@ -1452,7 +1446,7 @@ export async function rpcRequest(
       for (const [p, v] of sessionContext.syncState.downloadsValues) {
         const attrs = sessionContext.deviceData.attributes.get(p);
         if (attrs) {
-          if (attrs.writable && attrs.writable[1] && attrs.value) {
+          if (attrs.writable?.[1] && attrs.value) {
             const val = device.sanitizeParameterValue([v, attrs.value[1][1]]);
             if (val[0] !== attrs.value[1][0]) {
               toClear = device.set(
@@ -1693,7 +1687,7 @@ function generateGetRpcRequest(
       syncState.refreshAttributes.value.delete(path);
       // Need to check in case param is deleted or changed to object
       const attrs = sessionContext.deviceData.attributes.get(path);
-      if (attrs && attrs.object && attrs.object[1] === 0) {
+      if (attrs?.object?.[1] === 0) {
         parameterNames.push(path.toString());
         if (parameterNames.length >= GPV_BATCH_SIZE) break;
       }
@@ -1846,7 +1840,7 @@ function generateSetRpcRequest(
   for (const [k, v] of syncState.spv) {
     syncState.spv.delete(k);
     const attrs = sessionContext.deviceData.attributes.get(k);
-    const curVal = attrs.value ? attrs.value[1] : null;
+    const curVal = attrs.value?.[1];
     if (curVal && canWrite(attrs)) {
       const val = v.slice() as [string | number | boolean, string];
       if (!val[1]) val[1] = curVal[1];
@@ -1912,7 +1906,7 @@ function generateSetRpcRequest(
   for (const [p, t] of syncState.downloadsDownload) {
     if (!(t > 0 && t <= sessionContext.timestamp)) continue;
     const attrs = deviceData.attributes.get(p);
-    if (!(attrs && attrs.value && t <= attrs.value[1][0])) {
+    if (!(t <= attrs?.value?.[1]?.[0])) {
       const fileTypeAttrs = deviceData.attributes.get(
         deviceData.paths.get(p.slice(0, -1).concat(Path.parse("FileType")))
       );
@@ -1929,21 +1923,9 @@ function generateSetRpcRequest(
         name: "Download",
         commandKey: generateRpcId(sessionContext),
         instance: p.segments[1] as string,
-        fileType: fileTypeAttrs
-          ? fileTypeAttrs.value
-            ? (fileTypeAttrs.value[1][0] as string)
-            : null
-          : null,
-        fileName: fileNameAttrs
-          ? fileNameAttrs.value
-            ? (fileNameAttrs.value[1][0] as string)
-            : null
-          : null,
-        targetFileName: targetFileNameAttrs
-          ? targetFileNameAttrs.value
-            ? (targetFileNameAttrs.value[1][0] as string)
-            : null
-          : null,
+        fileType: fileTypeAttrs?.value?.[1][0] as string,
+        fileName: fileNameAttrs?.value?.[1][0] as string,
+        targetFileName: targetFileNameAttrs?.value?.[1][0] as string,
       };
     }
   }
@@ -1952,7 +1934,7 @@ function generateSetRpcRequest(
   if (syncState.reboot > 0 && syncState.reboot <= sessionContext.timestamp) {
     const p = sessionContext.deviceData.paths.get(Path.parse("Reboot"));
     const attrs = p ? sessionContext.deviceData.attributes.get(p) : null;
-    if (!(attrs && attrs.value && attrs.value[1][0] >= syncState.reboot)) {
+    if (!(attrs?.value?.[1][0] >= syncState.reboot)) {
       delete syncState.reboot;
       return { name: "Reboot" };
     }
@@ -1965,9 +1947,7 @@ function generateSetRpcRequest(
   ) {
     const p = sessionContext.deviceData.paths.get(Path.parse("FactoryReset"));
     const attrs = p ? sessionContext.deviceData.attributes.get(p) : null;
-    if (
-      !(attrs && attrs.value && attrs.value[1][0] >= syncState.factoryReset)
-    ) {
+    if (!(attrs?.value?.[1][0] >= syncState.factoryReset)) {
       delete syncState.factoryReset;
       return { name: "FactoryReset" };
     }
@@ -2035,7 +2015,7 @@ function generateSetVirtualParameterProvisions(
   let provisions;
   if (virtualParameterDeclarations) {
     for (const declaration of virtualParameterDeclarations) {
-      if (declaration[2] && declaration[2].value != null) {
+      if (declaration[2]?.value != null) {
         const attrs = sessionContext.deviceData.attributes.get(declaration[0]);
         if (
           attrs &&
@@ -2164,9 +2144,7 @@ function processDeclarations(
 
     if (currentAttributes) {
       leafParam = currentPath;
-      leafIsObject = currentAttributes.object
-        ? currentAttributes.object[1]
-        : null;
+      leafIsObject = currentAttributes.object?.[1];
       // Possible V8 bug causes null === 0
       if (leafIsObject != null && leafIsObject === 0)
         leafTimestamp = Math.max(leafTimestamp, currentAttributes.object[0]);
@@ -2181,13 +2159,13 @@ function processDeclarations(
     ) {
       case "Reboot":
         if (currentPath.length === 1) {
-          if (declareAttributeValues && declareAttributeValues.value)
+          if (declareAttributeValues?.value)
             syncState.reboot = +new Date(declareAttributeValues.value[0]);
         }
         break;
       case "FactoryReset":
         if (currentPath.length === 1) {
-          if (declareAttributeValues && declareAttributeValues.value)
+          if (declareAttributeValues?.value)
             syncState.factoryReset = +new Date(declareAttributeValues.value[0]);
         }
         break;
diff --git a/lib/ui.ts b/lib/ui.ts
index ac75910..dff76a1 100644
--- a/lib/ui.ts
+++ b/lib/ui.ts
@@ -62,7 +62,7 @@ const getAuthorizer = memoize(
 koa.on("error", async (err, ctx) => {
   setTimeout(() => {
     // Ignored errors resulting from aborted requests
-    if (ctx && ctx.req.aborted) return;
+    if (ctx?.req.aborted) return;
     throw err;
   });
 });
@@ -95,7 +95,7 @@ koa.use(
 koa.use(async (ctx, next) => {
   let roles: string[] = [];
 
-  if (ctx.state.user && ctx.state.user.username) {
+  if (ctx.state.user?.username) {
     let user;
     if (ctx.state.user.authMethod === "local") {
       user = localCache.getUsers(ctx.state.configSnapshot)[
diff --git a/lib/ui/api-functions.ts b/lib/ui/api-functions.ts
index 40823dd..c128a34 100644
--- a/lib/ui/api-functions.ts
+++ b/lib/ui/api-functions.ts
@@ -200,7 +200,7 @@ export function authLocal(
   return new Promise((resolve, reject) => {
     const users = getUsers(snapshot);
     const user = users[username];
-    if (!user || !user.password) return void resolve(null);
+    if (!user?.password) return void resolve(null);
     hashPassword(password, user.salt)
       .then((hash) => {
         if (hash === user.password) resolve(true);
diff --git a/lib/ui/api.ts b/lib/ui/api.ts
index 8867f58..427748c 100644
--- a/lib/ui/api.ts
+++ b/lib/ui/api.ts
@@ -573,12 +573,12 @@ router.post("/devices/:id/tasks", async (ctx) => {
       if (!Array.isArray(exp)) return exp;
       if (exp[0] === "PARAM") {
         const p = device[exp[1]];
-        if (p && p.value) return p.value[0];
+        if (p?.value) return p.value[0];
       } else if (exp[0] === "FUNC") {
         if (exp[1] === "REMOTE_ADDRESS") {
           for (const root of ["InternetGatewayDevice", "Device"]) {
             const p = device[`${root}.ManagementServer.ConnectionRequestURL`];
-            if (p && p.value) return new URL(p.value[0]).hostname;
+            if (p?.value) return new URL(p.value[0]).hostname;
           }
           return null;
         }
diff --git a/lib/ui/db.ts b/lib/ui/db.ts
index 8167441..cdacbb4 100644
--- a/lib/ui/db.ts
+++ b/lib/ui/db.ts
@@ -190,8 +190,8 @@ export async function updateDeviceTags(
   const collection = db.collection("devices");
   const object = {};
 
-  if (add && add.length) object["$addToSet"] = { _tags: { $each: add } };
-  if (pull && pull.length) object["$pullAll"] = { _tags: pull };
+  if (add?.length) object["$addToSet"] = { _tags: { $each: add } };
+  if (pull?.length) object["$pullAll"] = { _tags: pull };
 
   await collection.updateOne({ _id: deviceId }, object);
 }
@@ -242,7 +242,7 @@ export function putProvision(
       lineOffset: -1,
     });
   } catch (err) {
-    if (err.stack && err.stack.startsWith(`${id}:`)) {
+    if (err.stack?.startsWith(`${id}:`)) {
       return Promise.reject(
         new Error(`${err.name} at ${err.stack.split("\n", 1)[0]}`)
       );
@@ -267,7 +267,7 @@ export function putVirtualParameter(
       lineOffset: -1,
     });
   } catch (err) {
-    if (err.stack && err.stack.startsWith(`${id}:`)) {
+    if (err.stack?.startsWith(`${id}:`)) {
       return Promise.reject(
         new Error(`${err.name} at ${err.stack.split("\n", 1)[0]}`)
       );
diff --git a/tsconfig.json b/tsconfig.json
index 5a5f8d8..05acdf5 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,9 +1,9 @@
 {
   "compilerOptions": {
-    "lib": ["esnext", "dom"],
-    "module": "esnext",
+    "lib": ["ES2019", "dom"],
+    "module": "ES2020",
     "moduleResolution": "node",
-    "target": "esnext",
+    "target": "ES2019",
     "resolveJsonModule": true,
     "allowSyntheticDefaultImports": true,
     "alwaysStrict": true,
diff --git a/ui/app.ts b/ui/app.ts
index de2f8d8..f7c9b00 100644
--- a/ui/app.ts
+++ b/ui/app.ts
@@ -69,7 +69,7 @@ function pagify(pageName, page): RouteResolver {
     render: () => {
       const lastRenderTimestamp = Date.now();
       let p;
-      if (state && state.error) p = m(errorPage.component, state);
+      if (state?.error) p = m(errorPage.component, state);
       else p = m(contextifyComponent(page.component), state);
       const attrs = {};
       attrs["page"] = pageName;
diff --git a/ui/components.ts b/ui/components.ts
index 22ea558..aca53ee 100644
--- a/ui/components.ts
+++ b/ui/components.ts
@@ -116,7 +116,7 @@ function applyContext(vnode, parentContext): void {
       vnodeContext.set(vnode, vc);
       vnode.attrs = Object.assign({}, vc, vnode.attrs);
     }
-    if (vnode.children && vnode.children.length)
+    if (vnode.children?.length)
       for (const c of vnode.children) applyContext(c, vc);
   }
 }
@@ -133,7 +133,7 @@ export function contextifyComponent(component: ComponentTypes): ComponentTypes {
         applyContext(res, context);
         return res;
       };
-    } else if (!component.prototype || !component.prototype.view) {
+    } else if (!component.prototype?.view) {
       c = (initialNode) => {
         const state = (component as ClosureComponent)(initialNode);
         const view = state.view;
diff --git a/ui/components/all-parameters.ts b/ui/components/all-parameters.ts
index 3e9cff9..f1eb2c1 100644
--- a/ui/components/all-parameters.ts
+++ b/ui/components/all-parameters.ts
@@ -85,7 +85,7 @@ const component: ClosureComponent = (): Component => {
         let c = 0;
         for (const k of keys) {
           const p = device[k];
-          const str = p.value && p.value[0] ? `${k} ${p.value[0]}` : k;
+          const str = p.value?.[0] ? `${k} ${p.value[0]}` : k;
           if (re && !re.test(str)) continue;
           ++c;
           if (count < limit) filteredKeys.push(k);
diff --git a/ui/components/parameter.ts b/ui/components/parameter.ts
index 32dbd44..a15dead 100644
--- a/ui/components/parameter.ts
+++ b/ui/components/parameter.ts
@@ -38,7 +38,7 @@ const evaluateParam = memoize((exp, obj, now: number) => {
       ) {
         let v = null;
         const p = obj[e[i][1]];
-        if (p && p.value) {
+        if (p?.value) {
           v = p.value[0];
           timestamp = Math.min(timestamp, p.valueTimestamp);
         }
@@ -58,7 +58,7 @@ const evaluateParam = memoize((exp, obj, now: number) => {
     value = exp;
   } else if (exp[0] === "PARAM") {
     const p = obj[exp[1]];
-    if (p && p.value) {
+    if (p?.value) {
       timestamp = p.valueTimestamp;
       value = p.value[0];
       parameter = exp[1];
@@ -84,7 +84,7 @@ const component: ClosureComponent = (): Component => {
       if (value == null) return null;
 
       let edit;
-      if (device[parameter] && device[parameter].writable) {
+      if (device[parameter]?.writable) {
         edit = m(
           "button",
           {
diff --git a/ui/files-page.ts b/ui/files-page.ts
index 0531357..f650970 100644
--- a/ui/files-page.ts
+++ b/ui/files-page.ts
@@ -207,7 +207,7 @@ export const component: ClosureComponent = (): Component => {
                         actionHandler: async (action, obj) => {
                           if (action !== "save")
                             throw new Error("Undefined action");
-                          const file = obj["file"] ? obj["file"][0] : null;
+                          const file = obj["file"]?.[0];
 
                           // nginx strips out headers with dot, so replace with dash
                           const headers = {
diff --git a/ui/presets-page.ts b/ui/presets-page.ts
index f150167..ce69521 100644
--- a/ui/presets-page.ts
+++ b/ui/presets-page.ts
@@ -331,7 +331,7 @@ export const component: ClosureComponent = (): Component => {
                 overlay.open(
                   cb,
                   () =>
-                    !(comp.state && comp.state["current"]["modified"]) ||
+                    !comp.state?.["current"]["modified"] ||
                     confirm("You have unsaved changes. Close anyway?")
                 );
               },
diff --git a/ui/smart-query.ts b/ui/smart-query.ts
index 4976464..87cc5c5 100644
--- a/ui/smart-query.ts
+++ b/ui/smart-query.ts
@@ -145,7 +145,7 @@ function queryTag(tag: string): Expression {
 
 export function getTip(resource: string, label: string): string {
   let tip;
-  if (resources[resource] && resources[resource][label]) {
+  if (resources[resource]?.[label]) {
     const param = resources[resource][label];
     const types =
       resource === "devices" ? param["type"] : param["type"].split(",");