diff --git a/client/lib/patch-db.ts b/client/lib/patch-db.ts
index e5be7a1..5d8b894 100644
--- a/client/lib/patch-db.ts
+++ b/client/lib/patch-db.ts
@@ -1,5 +1,5 @@
 import { EMPTY, map, merge, Observable, shareReplay, Subject } from 'rxjs'
-import { catchError, switchMap } from 'rxjs/operators'
+import { catchError, filter, switchMap, tap } from 'rxjs/operators'
 import { Store } from './store'
 import { DBCache, Http } from './types'
 import { Source } from './source/source'
@@ -17,9 +17,10 @@ export class PatchDB<T> {
         }),
       ),
     ),
+    tap(_ => this.connectionError$.next(null)),
+    filter(Boolean),
     map(res => {
       this.store.update(res)
-
       return this.store.cache
     }),
     shareReplay(1),
diff --git a/client/lib/source/poll-source.ts b/client/lib/source/poll-source.ts
index 678bc4f..25c82c6 100644
--- a/client/lib/source/poll-source.ts
+++ b/client/lib/source/poll-source.ts
@@ -14,12 +14,20 @@ export class PollSource<T> implements Source<T> {
     private readonly http: Http<T>,
   ) {}
 
-  watch$({ sequence$ }: Store<T>): Observable<Update<T>> {
+  watch$({ sequence$ }: Store<T>): Observable<Update<T> | null> {
     return sequence$.pipe(
       concatMap(seq => this.http.getRevisions(seq)),
       take(1),
-      // convert Revision[] it into Observable<Revision>. Convert Dump<T> into Observable<Dump<T>>
-      concatMap(res => (Array.isArray(res) ? from(res) : of(res))),
+      concatMap(res => {
+        // If Revision[]
+        if (Array.isArray(res)) {
+          // Convert Revision[] it into Observable<Revision> OR return null
+          return res.length ? from(res) : of(null)
+          // If Dump<T>
+        }
+        // Convert Dump<T> into Observable<Dump<T>>
+        return of(res)
+      }),
       repeat({ delay: this.pollConfig.cooldown }),
     )
   }
diff --git a/client/lib/source/source.ts b/client/lib/source/source.ts
index 4e69eb0..ce5197f 100644
--- a/client/lib/source/source.ts
+++ b/client/lib/source/source.ts
@@ -3,5 +3,5 @@ import { Store } from '../store'
 import { Update } from '../types'
 
 export interface Source<T> {
-  watch$(store?: Store<T>): Observable<Update<T>>
+  watch$(store?: Store<T>): Observable<Update<T> | null>
 }
diff --git a/client/package.json b/client/package.json
index 8d86da0..51cbd57 100644
--- a/client/package.json
+++ b/client/package.json
@@ -15,7 +15,7 @@
     "uuid": "8.3.2"
   },
   "peerDependencies": {
-    "rxjs": ">=6.0.0"
+    "rxjs": ">=7.0.0"
   },
   "devDependencies": {
     "@types/node": "16.4.13",