diff --git a/.flowconfig b/.flowconfig
index 3cf493d..7dd029c 100644
--- a/.flowconfig
+++ b/.flowconfig
@@ -14,6 +14,9 @@
 .*/Libraries/react-native/React.js
 .*/Libraries/react-native/ReactNative.js
 
+; Ignore generated files from the android build
+.*/android/app/build/.*
+
 [include]
 
 [libs]
diff --git a/app/components/Avatar/index.js b/app/components/Avatar/index.js
index 906caa6..93a5a54 100644
--- a/app/components/Avatar/index.js
+++ b/app/components/Avatar/index.js
@@ -7,7 +7,7 @@ import theme from '../../theme';
 type Props = {
   size?: number,
   source: string,
-  style: Object | null | Array<Object | null>,
+  style?: mixed,
 };
 
 export default function Avatar({ size = 44, source, style, ...props }: Props) {
diff --git a/app/components/Navbar/components/NavbarAndroid/index.js b/app/components/Navbar/components/NavbarAndroid/index.js
index 4657273..7e12f74 100644
--- a/app/components/Navbar/components/NavbarAndroid/index.js
+++ b/app/components/Navbar/components/NavbarAndroid/index.js
@@ -15,6 +15,7 @@ import theme from '../../../../theme';
 
 type Props = {
   backgroundColor?: string,
+  buttonColor?: string,
   leftButtonDisabled?: boolean,
   leftButtonIconName?: string,
   leftButtonOnPress?: () => mixed,
@@ -23,6 +24,7 @@ type Props = {
   rightButtonIconName?: string,
   rightButtonOnPress?: () => mixed,
   rightButtonText?: string,
+  textColor?: string,
   title: string,
   titleRenderer?: () => mixed,
 };
diff --git a/app/scenes/Schedule/components/Talk/index.js b/app/scenes/Schedule/components/Talk/index.js
index a742c1f..fe64302 100644
--- a/app/scenes/Schedule/components/Talk/index.js
+++ b/app/scenes/Schedule/components/Talk/index.js
@@ -85,8 +85,8 @@ function KeynoteSubtitle({ text, ...props }) {
 // ==============================
 
 type Props = {
-  keynote: boolean,
-  lightning: boolean,
+  keynote?: boolean,
+  lightning?: boolean,
   onPress: () => mixed,
   speaker: Object,
   startTime: string,
diff --git a/app/scenes/Talk/components/Pane/index.js b/app/scenes/Talk/components/Pane/index.js
index 7f3ae70..358a81e 100644
--- a/app/scenes/Talk/components/Pane/index.js
+++ b/app/scenes/Talk/components/Pane/index.js
@@ -14,7 +14,7 @@ import {
 } from 'react-native';
 import moment from 'moment';
 
-import type { ScheduleTalk } from '../../../../types';
+import type { ScheduleTalk, SpeakerType } from '../../../../types';
 
 import { TIME_FORMAT } from '../../../../constants';
 import { darken } from '../../../../utils/color';
@@ -44,20 +44,21 @@ function Speaker({ data, onPress }) {
   );
 }
 
-export default class TalkPane extends Component {
-  props: {
-    nextTalk?: ScheduleTalk | null,
-    nextTalkPreviewIsEngaged?: boolean,
-    onHeroLayout?: (Object) => mixed,
-    onPressNext?: (Object) => mixed,
-    onScroll?: (Object) => mixed,
-    onScrollEndDrag?: () => mixed,
-    prevTalk?: ScheduleTalk | null,
-    prevTalkPreviewIsEngaged?: boolean,
-    showSpeakerModal?: () => mixed,
-    visibleTalk: ScheduleTalk,
-  };
+type Props = {
+  nextTalk?: ScheduleTalk | null,
+  nextTalkPreviewIsEngaged?: boolean,
+  onHeroLayout?: (Object) => mixed,
+  onPressNext?: (Object) => mixed,
+  onScroll?: (Object) => mixed,
+  onScrollEndDrag?: () => mixed,
+  prevTalk?: ScheduleTalk | null,
+  prevTalkPreviewIsEngaged?: boolean,
+  showSpeakerModal: (SpeakerType | Array<SpeakerType>) => mixed,
+  visibleTalk: ScheduleTalk,
+};
 
+export default class TalkPane extends Component {
+  props: Props;
   state = {
     animValue: new Animated.Value(0),
   };
@@ -67,7 +68,7 @@ export default class TalkPane extends Component {
       this.fadeInAdroidNextButton();
     }
   }
-  componentWillReceiveProps(nextProps) {
+  componentWillReceiveProps(nextProps: Props) {
     const isAndroid = Platform.OS === 'android';
     const isNewTalk = (this.props.nextTalk && this.props.nextTalk.id) !==
       (nextProps.nextTalk && nextProps.nextTalk.id);
diff --git a/app/scenes/Talk/index.js b/app/scenes/Talk/index.js
index 3b00568..1b0f9aa 100644
--- a/app/scenes/Talk/index.js
+++ b/app/scenes/Talk/index.js
@@ -24,8 +24,8 @@ import TalkPane from './components/Pane';
 
 type Props = {
   navigator: Object,
-  nextTalk: ScheduleTalk | null,
-  prevTalk: ScheduleTalk | null,
+  nextTalk?: ScheduleTalk,
+  prevTalk?: ScheduleTalk,
   talk: ScheduleTalk,
   introduceUI: boolean,
 };
@@ -35,19 +35,19 @@ type TransitionDirection = 'prev' | 'next';
 type State = {
   animValue: Animated.Value,
   modalIsOpen: boolean,
-  modalSpeaker: SpeakerType | null,
-  nextTalk: ScheduleTalk | null,
-  prevTalk: ScheduleTalk | null,
+  modalSpeaker?: SpeakerType,
+  nextTalk?: ScheduleTalk,
+  prevTalk?: ScheduleTalk,
   showIntro: boolean,
   talk: ScheduleTalk,
-  incomingTalk?: ScheduleTalk | null,
+  incomingTalk?: ScheduleTalk,
   transitionDirection?: TransitionDirection,
 };
 
 type SetTalksState = {
   talk: ScheduleTalk,
-  nextTalk: ScheduleTalk | null,
-  prevTalk: ScheduleTalk | null,
+  nextTalk?: ScheduleTalk,
+  prevTalk?: ScheduleTalk,
 };
 
 class Talk extends Component {
diff --git a/app/types.js b/app/types.js
index c61713f..22c7835 100644
--- a/app/types.js
+++ b/app/types.js
@@ -5,28 +5,24 @@ export type ScheduleTimeRange = {
   end: Date,
 };
 
+export type SpeakerType = {
+  avatar: string,
+  github?: string,
+  name: string,
+  twitter?: string,
+  summary: string,
+};
+
 export type ScheduleTalk = {
   id: string,
+  keynote: boolean,
+  lightning: boolean,
   summary: string,
   title: string,
-  speaker: {
-    avatar: string,
-    github?: string,
-    name: string,
-    twitter?: string,
-    summary: string,
-  },
+  speaker: SpeakerType | Array<SpeakerType>,
   time: ScheduleTimeRange,
 };
 
-export type SpeakerType = {
-  avatar: string,
-  github: string,
-  name: string,
-  summary: string,
-  twitter: string,
-};
-
 export type ScheduleBreak = {
   break: true,
   time: ScheduleTimeRange,