diff --git a/src/components/location-search.tsx b/src/components/location-search.tsx
index 9867a52fb..48b8c4b8a 100644
--- a/src/components/location-search.tsx
+++ b/src/components/location-search.tsx
@@ -2,7 +2,6 @@ import backspaceIcon from '@tabler/icons/outline/backspace.svg';
 import searchIcon from '@tabler/icons/outline/search.svg';
 import clsx from 'clsx';
 import { throttle } from 'es-toolkit';
-import { OrderedSet as ImmutableOrderedSet } from 'immutable';
 import { useCallback, useEffect, useRef, useState } from 'react';
 import { defineMessages, useIntl } from 'react-intl';
 
@@ -26,7 +25,7 @@ interface ILocationSearch {
 const LocationSearch: React.FC<ILocationSearch> = ({ onSelected }) => {
   const intl = useIntl();
   const dispatch = useAppDispatch();
-  const [locationIds, setLocationIds] = useState(ImmutableOrderedSet<string>());
+  const [locationIds, setLocationIds] = useState(new Set<string>());
   const controller = useRef(new AbortController());
 
   const [value, setValue] = useState('');
@@ -67,14 +66,14 @@ const LocationSearch: React.FC<ILocationSearch> = ({ onSelected }) => {
   };
 
   const clearResults = () => {
-    setLocationIds(ImmutableOrderedSet());
+    setLocationIds(new Set<string>());
   };
 
   const handleLocationSearch = useCallback(throttle(q => {
     dispatch(locationSearch(q, controller.current.signal))
       .then((locations: { origin_id: string }[]) => {
         const locationIds = locations.map(location => location.origin_id);
-        setLocationIds(ImmutableOrderedSet(locationIds));
+        setLocationIds(new Set<string>(locationIds));
       })
       .catch(noOp);
 
@@ -93,7 +92,7 @@ const LocationSearch: React.FC<ILocationSearch> = ({ onSelected }) => {
         placeholder={intl.formatMessage(messages.placeholder)}
         value={value}
         onChange={handleChange}
-        suggestions={locationIds.toList()}
+        suggestions={Array.from(locationIds)}
         onSuggestionsFetchRequested={noOp}
         onSuggestionsClearRequested={noOp}
         onSuggestionSelected={handleSelected}
diff --git a/src/features/compose/components/polls/poll-form.tsx b/src/features/compose/components/polls/poll-form.tsx
index 98313325e..666ec4d9b 100644
--- a/src/features/compose/components/polls/poll-form.tsx
+++ b/src/features/compose/components/polls/poll-form.tsx
@@ -156,7 +156,7 @@ const PollForm: React.FC<IPollForm> = ({ composeId }) => {
             onChange={onChangeOption}
             onRemove={onRemoveOption}
             maxChars={maxOptionChars}
-            numOptions={options.size}
+            numOptions={options.length}
             onRemovePoll={onRemovePoll}
           />
         ))}
@@ -164,7 +164,7 @@ const PollForm: React.FC<IPollForm> = ({ composeId }) => {
         <HStack space={2}>
           <div className='w-6' />
 
-          {options.size < maxOptions && (
+          {options.length < maxOptions && (
             <Button
               theme='secondary'
               onClick={handleAddOption}
diff --git a/src/features/compose/components/search-results.tsx b/src/features/compose/components/search-results.tsx
index 716db2f70..5bdab7695 100644
--- a/src/features/compose/components/search-results.tsx
+++ b/src/features/compose/components/search-results.tsx
@@ -1,5 +1,6 @@
 import xIcon from '@tabler/icons/outline/x.svg';
 import clsx from 'clsx';
+import { OrderedSet as ImmutableOrderedSet } from 'immutable';
 import { useEffect, useRef } from 'react';
 import { FormattedMessage, defineMessages, useIntl } from 'react-intl';
 
@@ -21,7 +22,6 @@ import PlaceholderStatus from 'soapbox/features/placeholder/components/placehold
 import { useAppDispatch } from 'soapbox/hooks/useAppDispatch.ts';
 import { useAppSelector } from 'soapbox/hooks/useAppSelector.ts';
 
-import type { OrderedSet as ImmutableOrderedSet } from 'immutable';
 import type { VirtuosoHandle } from 'react-virtuoso';
 import type { SearchFilter } from 'soapbox/reducers/search.ts';
 
@@ -198,7 +198,7 @@ const SearchResults = () => {
     placeholderComponent = PlaceholderHashtag;
 
     if (results.hashtags && results.hashtags.size > 0) {
-      searchResults = results.hashtags.map(hashtag => <Hashtag key={hashtag.name} hashtag={hashtag} />);
+      searchResults = [...results.hashtags].map(hashtag => <Hashtag key={hashtag.name} hashtag={hashtag} />);
     } else if (!submitted && suggestions && !suggestions.isEmpty()) {
       searchResults = trends.map(hashtag => <Hashtag key={hashtag.name} hashtag={hashtag} />);
     } else if (loaded) {
@@ -236,7 +236,11 @@ const SearchResults = () => {
           key={selectedFilter}
           scrollKey={`${selectedFilter}:${value}`}
           isLoading={submitted && !loaded}
-          showLoading={submitted && !loaded && searchResults?.isEmpty()}
+          showLoading={submitted && !loaded && (
+            !searchResults ||
+            (Array.isArray(searchResults) && searchResults.length === 0) ||
+            (ImmutableOrderedSet.isOrderedSet(searchResults) && searchResults.size === 0)
+          )}
           hasMore={hasMore}
           onLoadMore={handleLoadMore}
           placeholderComponent={placeholderComponent}
diff --git a/src/features/compose/components/upload-form.tsx b/src/features/compose/components/upload-form.tsx
index 290d0b3b8..632a19719 100644
--- a/src/features/compose/components/upload-form.tsx
+++ b/src/features/compose/components/upload-form.tsx
@@ -42,7 +42,7 @@ const UploadForm: React.FC<IUploadForm> = ({ composeId, onSubmit }) => {
     <div className='overflow-hidden'>
       <UploadProgress composeId={composeId} />
 
-      <HStack wrap className={clsx('overflow-hidden', mediaIds.size !== 0 && 'p-1')}>
+      <HStack wrap className={clsx('overflow-hidden', mediaIds.length !== 0 && 'p-1')}>
         {mediaIds.map((id: string) => (
           <Upload
             id={id}
diff --git a/src/features/compose/containers/quoted-status-container.tsx b/src/features/compose/containers/quoted-status-container.tsx
index 3fdd0f66a..961039f53 100644
--- a/src/features/compose/containers/quoted-status-container.tsx
+++ b/src/features/compose/containers/quoted-status-container.tsx
@@ -15,7 +15,7 @@ const QuotedStatusContainer: React.FC<IQuotedStatusContainer> = ({ composeId })
   const dispatch = useAppDispatch();
   const getStatus = useCallback(makeGetStatus(), []);
 
-  const status = useAppSelector(state => getStatus(state, { id: state.compose.get(composeId)?.quote! }));
+  const status = useAppSelector(state => getStatus(state, { id: state.compose[composeId]?.quote! }));
 
   const onCancel = () => {
     dispatch(cancelQuoteCompose());
diff --git a/src/features/compose/containers/reply-indicator-container.ts b/src/features/compose/containers/reply-indicator-container.ts
index b2399abc2..8360b1305 100644
--- a/src/features/compose/containers/reply-indicator-container.ts
+++ b/src/features/compose/containers/reply-indicator-container.ts
@@ -14,8 +14,8 @@ const makeMapStateToProps = () => {
   const getStatus = makeGetStatus();
 
   const mapStateToProps = (state: RootState, { composeId }: { composeId: string }) => {
-    const statusId = state.compose.get(composeId)?.in_reply_to!;
-    const editing = !!state.compose.get(composeId)?.id;
+    const statusId = state.compose[composeId]?.in_reply_to!;
+    const editing = !!state.compose[composeId]?.id;
 
     return {
       status: (getStatus(state, { id: statusId }) as LegacyStatus)?.toJS() as StatusEntity,
diff --git a/src/features/compose/containers/upload-button-container.ts b/src/features/compose/containers/upload-button-container.ts
index 6ead8ee37..2d13928a8 100644
--- a/src/features/compose/containers/upload-button-container.ts
+++ b/src/features/compose/containers/upload-button-container.ts
@@ -8,8 +8,8 @@ import type { IntlShape } from 'react-intl';
 import type { AppDispatch, RootState } from 'soapbox/store.ts';
 
 const mapStateToProps = (state: RootState, { composeId }: { composeId: string }) => ({
-  disabled: state.compose.get(composeId)?.is_uploading,
-  resetFileKey: state.compose.get(composeId)?.resetFileKey!,
+  disabled: state.compose[composeId]?.is_uploading,
+  resetFileKey: state.compose[composeId]?.resetFileKey!,
 });
 
 const mapDispatchToProps = (dispatch: AppDispatch, { composeId }: { composeId: string }) => ({
diff --git a/src/features/compose/editor/index.tsx b/src/features/compose/editor/index.tsx
index 1ba2505b0..f2b53ebb3 100644
--- a/src/features/compose/editor/index.tsx
+++ b/src/features/compose/editor/index.tsx
@@ -94,7 +94,7 @@ const ComposeEditor = forwardRef<LexicalEditor, IComposeEditor>(({
     theme,
     editorState: dispatch((_, getState) => {
       const state = getState();
-      const compose = state.compose.get(composeId);
+      const compose = state.compose[composeId];
 
       if (!compose) return;
 
diff --git a/src/features/compose/editor/plugins/autosuggest-plugin.tsx b/src/features/compose/editor/plugins/autosuggest-plugin.tsx
index 984dea262..c85daa54e 100644
--- a/src/features/compose/editor/plugins/autosuggest-plugin.tsx
+++ b/src/features/compose/editor/plugins/autosuggest-plugin.tsx
@@ -297,7 +297,7 @@ const AutosuggestPlugin = ({
   };
 
   const onSelectSuggestion = (index: number) => {
-    const suggestion = suggestions.get(index) as AutoSuggestion;
+    const suggestion = suggestions[index] as AutoSuggestion;
 
     editor.update(() => {
       dispatch((dispatch, getState) => {
@@ -443,11 +443,11 @@ const AutosuggestPlugin = ({
   ]);
 
   useEffect(() => {
-    if (suggestions && suggestions.size > 0) setSuggestionsHidden(false);
+    if (suggestions && suggestions.length > 0) setSuggestionsHidden(false);
   }, [suggestions]);
 
   useEffect(() => {
-    if (resolution !== null && !suggestionsHidden && !suggestions.isEmpty()) {
+    if (resolution !== null && !suggestionsHidden && suggestions.length > 0) {
       const handleClick = (event: MouseEvent) => {
         const target = event.target as HTMLElement;
 
@@ -459,7 +459,7 @@ const AutosuggestPlugin = ({
 
       return () => document.removeEventListener('click', handleClick);
     }
-  }, [resolution, suggestionsHidden, suggestions.isEmpty()]);
+  }, [resolution, suggestionsHidden, suggestions.length === 0]);
 
   useEffect(() => {
     if (resolution === null) return;
@@ -469,8 +469,8 @@ const AutosuggestPlugin = ({
         KEY_ARROW_UP_COMMAND,
         (payload) => {
           const event = payload;
-          if (suggestions !== null && suggestions.size && selectedSuggestion !== null) {
-            const newSelectedSuggestion = selectedSuggestion !== 0 ? selectedSuggestion - 1 : suggestions.size - 1;
+          if (suggestions !== null && suggestions.length && selectedSuggestion !== null) {
+            const newSelectedSuggestion = selectedSuggestion !== 0 ? selectedSuggestion - 1 : suggestions.length - 1;
             setSelectedSuggestion(newSelectedSuggestion);
             event.preventDefault();
             event.stopImmediatePropagation();
@@ -483,8 +483,8 @@ const AutosuggestPlugin = ({
         KEY_ARROW_DOWN_COMMAND,
         (payload) => {
           const event = payload;
-          if (suggestions !== null && suggestions.size && selectedSuggestion !== null) {
-            const newSelectedSuggestion = selectedSuggestion !== suggestions.size - 1 ? selectedSuggestion + 1 : 0;
+          if (suggestions !== null && suggestions.length && selectedSuggestion !== null) {
+            const newSelectedSuggestion = selectedSuggestion !== suggestions.length - 1 ? selectedSuggestion + 1 : 0;
             setSelectedSuggestion(newSelectedSuggestion);
             event.preventDefault();
             event.stopImmediatePropagation();
@@ -540,8 +540,8 @@ const AutosuggestPlugin = ({
             <div
               className={clsx({
                 'scroll-smooth snap-y snap-always will-change-scroll mt-6 overflow-y-auto max-h-56 relative w-max z-[1000] shadow bg-white dark:bg-gray-900 rounded-lg py-1 space-y-0 dark:ring-2 dark:ring-primary-700 focus:outline-none': true,
-                hidden: suggestionsHidden || suggestions.isEmpty(),
-                block: !suggestionsHidden && !suggestions.isEmpty(),
+                hidden: suggestionsHidden || suggestions.length === 0,
+                block: !suggestionsHidden && suggestions.length > 0,
               })}
             >
               {suggestions.map(renderSuggestion)}
diff --git a/src/features/group/group-timeline.tsx b/src/features/group/group-timeline.tsx
index 47a5a6a51..9ff9052a7 100644
--- a/src/features/group/group-timeline.tsx
+++ b/src/features/group/group-timeline.tsx
@@ -42,7 +42,7 @@ const GroupTimeline: React.FC<IGroupTimeline> = (props) => {
 
   const composeId = `group:${groupId}`;
   const canComposeGroupStatus = !!account && group?.relationship?.member;
-  const groupTimelineVisible = useAppSelector((state) => !!state.compose.get(composeId)?.group_timeline_visible);
+  const groupTimelineVisible = useAppSelector((state) => !!state.compose[composeId]?.group_timeline_visible);
   const featuredStatusIds = useAppSelector((state) => getStatusIds(state, { type: `group:${group?.id}:pinned` }));
 
   const { isDragging, isDraggedOver } = useDraggedFiles(composer, (files) => {
diff --git a/src/features/reply-mentions/account.tsx b/src/features/reply-mentions/account.tsx
index 5fee68893..ae8df9d9c 100644
--- a/src/features/reply-mentions/account.tsx
+++ b/src/features/reply-mentions/account.tsx
@@ -29,7 +29,7 @@ const Account: React.FC<IAccount> = ({ composeId, accountId, author }) => {
 
   const compose = useCompose(composeId);
   const { account } = useAccount(accountId);
-  const added = !!account && compose.to?.includes(account.acct);
+  const added = !!account && Array.from(compose.to)?.includes(account.acct);
 
   const onRemove = () => dispatch(removeFromMentions(composeId, accountId));
   const onAdd = () => dispatch(addToMentions(composeId, accountId));