Code Theory

Reference

Technology status

Every API, library and platform covered on this site, and what has happened to it since the guide was written. Checked against vendor documentation as of August 2026.

31 Still current
22 Superseded
11 Removed
Android technology status
Technology Status Replaced by Notes
AsyncTask Superseded

Android 11 (API 30)

Kotlin coroutines, or java.util.concurrent for Java projects Deprecated for leaking activities and swallowing exceptions on the default executor.
ListView / GridView Superseded

RecyclerView, 2014

RecyclerView with a LayoutManager View recycling and the adapter contract carry over almost unchanged.
ExpandableListView Superseded

RecyclerView, 2014

RecyclerView with multiple view types, or nested lists
ViewPager Superseded

ViewPager2, 2019

ViewPager2 Built on RecyclerView; adds vertical paging and right-to-left support.
PagerTabStrip / PagerTitleStrip Superseded

Material Components

TabLayout attached to a ViewPager2
Framework ActionBar Superseded

AppCompat

androidx Toolbar / MaterialToolbar The framework ActionBar is not themable across versions; the AndroidX one is.
Loader framework (LoaderManager, CursorLoader) Superseded

Android 9 (API 28)

ViewModel with LiveData or Kotlin Flow The lifecycle-aware loading idea survived; this implementation of it did not.
IntentService Superseded

Android 11 (API 30)

WorkManager for deferrable work, foreground services for the rest Background execution limits from API 26 are what made it unworkable.
SharedPreferences Superseded

Jetpack DataStore, 2020

Jetpack DataStore (Preferences or Proto) Still works and is still everywhere; DataStore is the recommendation for new code.
Direct SQLite (SQLiteOpenHelper) Superseded

Room, 2017

Room Room compiles the same SQL but checks it at build time.
Google Cloud Messaging (GCM) Removed

Shut down 2019

Firebase Cloud Messaging (FCM) The service no longer accepts registrations. Guides pruned.
Parse (hosted service) Removed

Shut down January 2017

Parse Platform self-hosted, or Firebase The open-source server continues; the hosted backend the guides used does not.
PhoneGap / PhoneGap Build Removed

Discontinued October 2020

Apache Cordova, or Capacitor Cordova itself is still maintained; Adobe’s distribution and build service are not.
HierarchyViewer Removed

Removed from the SDK

Layout Inspector in Android Studio
Intents and intent filters Current Background broadcast restrictions apply from API 26 onward.
Services and bound services Current Foreground service types are mandatory from API 34.
AIDL and Binder IPC Current Unchanged; still the substrate the whole platform sits on.
Content providers Current Scoped storage from API 29 changes what they may expose.
Handler, Looper, MessageQueue Current
GestureDetector and touch events Current pointerInput in Jetpack Compose, for Compose UIs The View-system pipeline described is unchanged.
adb Current Wireless debugging is built into the developer options from Android 11.
View system (XML layouts) Superseded

Jetpack Compose, 2021

Jetpack Compose The largest gap on this site: every Android guide here predates Compose.
HTML5 technology status
Technology Status Replaced by Notes
Canvas 2D context Current Unchanged. These guides are as correct now as when written.
Web Audio API Current AudioWorklet replaced ScriptProcessorNode for custom processing.
requestAnimationFrame Current
HTML5 form constraint validation Current
Mobile audio autoplay restrictions Current Still gated on a user gesture; the workarounds described still apply.
Canvas for games Current WebGL2 or WebGPU for anything heavier WebGPU is the current direction for GPU work in the browser.
CSS technology status
Technology Status Replaced by Notes
backdrop-filter Current Was experimental when written; now supported across all major engines.
touch-action Current
box-shadow, gradients, filters Current
CSS animations and transitions Current Scroll-driven animations are the notable addition since.
Vendor prefixes (-webkit-) Superseded Unprefixed properties; autoprefixer where support demands it The prefix tables in these guides are mostly historical now.
Float and positioning layout Superseded

Flexbox and Grid

Flexbox, Grid, and container queries A gap: the layout guides here predate Grid entirely.
OOCSS / BEM / SMACSS Current BEM is still widely used; CSS Modules and utility-first CSS now sit alongside it.
node-sass Removed

Deprecated

dart-sass (the `sass` package) Anything invoking node-sass will not install on a current Node.
JavaScript technology status
Technology Status Replaced by Notes
document.execCommand Superseded

Deprecated

The async Clipboard API (navigator.clipboard) execCommand still works in practice but is specified as deprecated.
ReactDOM.unmountComponentAtNode Removed

React 18

root.unmount() on a root from createRoot
ReactDOM.render Removed

React 18

createRoot(container).render()
React legacy context (childContextTypes) Removed

React 16.3 introduced the replacement

createContext with a Provider and the useContext hook
Material-UI v0 (LeftNav, AppBar) Removed

Renamed to MUI

MUI Drawer and AppBar The component names in these guides no longer exist.
Class components and lifecycle methods Superseded

React 16.8 hooks, 2019

Function components with hooks A gap: every React guide here predates hooks.
Browserify Superseded Vite, esbuild or Rollup
Babel 6 Superseded

Babel 7, 2018

Current Babel, or esbuild/SWC for transpilation Guide pruned — the in-browser workflow it described is gone.
Underscore.string Superseded

ES2015+

Native String methods (padStart, trimEnd, replaceAll)
CoffeeScript Superseded

ES2015+

TypeScript, or modern JavaScript Guides pruned.
jQuery Superseded querySelectorAll, fetch, classList and the native DOM Still maintained; rarely chosen for new work.
postMessage / cross-origin messaging Current Origin checking remains as important as the guide says.
WebSockets Current
Node.js core APIs Current ESM is the default module system for new projects.
Backend technology status
Technology Status Replaced by Notes
PHPExcel Removed

Archived 2019

PhpSpreadsheet Direct successor from the same authors; the API is close but not identical.
Rails and Rack Current Rack 3 changed the response-body contract for middleware.
RSpec mocks and stubs Current
Devise and OmniAuth Current
Laravel Current Auth scaffolding moved to Breeze/Jetstream since these were written.
MySQL Current
AMP Superseded

2021

Core Web Vitals on the canonical page No longer required for Google Top Stories, and no longer a ranking factor.
Tools technology status
Technology Status Replaced by Notes
Chrome DevTools Current Panels have moved; the techniques hold.
ffmpeg Current
ImageMagick / GhostScript Current ImageMagick 7 changed the CLI entry point from `convert` to `magick`.
grep, fuser and core Unix utilities Current
Git and GitHub Current
Sublime Text Superseded VS Code, or a JetBrains IDE Guide pruned — a 2014 theme roundup for an editor most developers have left.
Genymotion ADB conflict Removed

Fixed upstream

The bundled Android Studio emulator Guide pruned — the version conflict it works around no longer occurs.