diff --git a/src/utils/fallback-provider.ts b/src/utils/fallback-provider.ts
index 561d48f..aef9995 100644
--- a/src/utils/fallback-provider.ts
+++ b/src/utils/fallback-provider.ts
@@ -1,4 +1,4 @@
-import { FallbackProvider, Networkish, WebSocketProvider } from 'ethers';
+import { FallbackProvider, Network, WebSocketProvider } from 'ethers';
 import { PollingJsonRpcProvider } from './polling-json-rpc-provider';
 
 export type FallbackProviderJsonConfig = {
@@ -17,8 +17,8 @@ export type ProviderJson = {
 export const createFallbackProviderFromJsonConfig = (
   config: FallbackProviderJsonConfig,
 ): FallbackProvider => {
-  const network: Networkish = Number(config.chainId);
   try {
+    const network = Network.from(Number(config.chainId));
     const providers = config.providers.map(json => {
       const isWebsocket = json.provider.startsWith('wss');
       const provider = isWebsocket
diff --git a/src/utils/polling-json-rpc-provider.ts b/src/utils/polling-json-rpc-provider.ts
index 493b645..2e70dcf 100644
--- a/src/utils/polling-json-rpc-provider.ts
+++ b/src/utils/polling-json-rpc-provider.ts
@@ -1,12 +1,15 @@
-import { JsonRpcProvider, JsonRpcApiProviderOptions, Networkish } from 'ethers';
+import { JsonRpcProvider, JsonRpcApiProviderOptions, Network } from 'ethers';
 
 /**
  * Uses a setting in JsonRpcProvider to poll for events,
  * rather than using sparsely-implemented eth_filter events.
  */
 export class PollingJsonRpcProvider extends JsonRpcProvider {
-  constructor(url: string, network: Networkish, disableBatching = false) {
-    const options: JsonRpcApiProviderOptions = { polling: true };
+  constructor(url: string, network: Network, disableBatching = false) {
+    const options: JsonRpcApiProviderOptions = {
+      polling: true,
+      staticNetwork: network,
+    };
     if (disableBatching) {
       options.batchMaxCount = 1;
     }