Twitter has announced an update for its iPhone and Android apps that offers an improved experience when viewing the Discover tab and adds a new persistent search button (iPhone version). The new Discover tab aggregates tweets, activity, trends, and suggestions of accounts to follow into one stream, while the search feature has been similarly upgraded to surface tweets, accounts, and photos all in the same stream. The iPhone app also gains a persistent search button next to the tweet compose button, letting users initiate searches from wherever they are in the app (the Android version has had this feature for some time).
Finally, Twitter has enabled the ability to directly go to a URL from your timeline with one click, eliminating the need to expand the tweet first. Overall, these updates are pretty minor, but they should make it easier for casual users to search the service while on the go. The updated apps should be available in the iTunes App Store or Google Play Store in the near future.
Update: Twitter just announced that its new search feature has an additional update — while previously search would only display tweets from up to a week ago, you should now start to see older tweets show up in your results. The feature is currently rolling out across mobile and web.