cross-posted from: https://lemmy.ml/post/1465740 > ## What is Lemmy? > > Lemmy is a self-hosted social link aggregation and discussion platform. It is completely free and open, and not controlled by any company. This means that there is no advertising, tracking, or secret algorithms. Content is organized into communities, so it is easy to subscribe to topics that you are interested in, and ignore others. Voting is used to bring the most interesting items to the top. > > ## Major Changes > > ### HTTP API instead of Websocket > > Until now Lemmy-UI used websocket for all API requests. This has [many disadvantages](https://github.com/LemmyNet/lemmy/issues/2841#issuecomment-1535469357), like making the code harder to maintain, and causing live updates to the site which many users dislike. Most importantly, it requires keeping a connection open between server and client at all times, which causes increased load and makes scaling difficult. That's why we decided to rip out websocket entirely, and switch to HTTP instead. This change was made much more urgent by the sudden influx of new users. [@CannotSleep420](https://lemmygrad.ml/u/CannotSleep420) and [@dessalines](https://lemmy.ml/u/dessalines) have been working hard for the past weeks to implement this change in lemmy-ui. > > HTTP on its own is already more lightweight than websocket. Additionally it also allows for caching of server responses which can decrease load on the database. Here is an [experimental nginx config](https://github.com/LemmyNet/lemmy-ansible/pull/75) which enables response caching. Note that Lemmy doesn't send any cache-control headers yet, so there is a chance that private data gets cached and served to other users. Test carefully and use at your own risk. > > ### Two-Factor Authentication > > New support for two-factor authentication. Use an app like [andOTP](https://f-droid.org/es/packages/org.shadowice.flocke.andotp/) or [Authenticator Pro]( > https://f-droid.org/packages/me.jmh.authenticatorpro/) to store a secret for your account. This secret needs to be entered every time you login. It ensures that an attacker can't access your account with the password alone. > > ### Custom Emojis > > Instance admins can add different images as emojis which can be referenced by users when posting. > > ### Other changes > > #### Progressive Web App > > Lemmy's web client can now be installed on browsers that support PWAs, both on desktop and mobile. It will use an instance's icon and name for the app if they are set, making it look like a given instance is an app. > > **Note for desktop Firefox users**: the desktop version of Firefox does not have built in support for PWAs. If you would like to use a Lemmy instance as a PWA, use [use this extension](https://addons.mozilla.org/en-US/firefox/addon/pwas-for-firefox/). > > #### Error Pages > > Lemmy's web client now has error pages that include resources to use if the problem persists. This should be much less jarring for users than displaying a white screen with the text "404 *error message here*". > > #### Route Changes > > Pages that took arguments in the route now take query parameters instead. For example, a link to lemmy.ml's home page with a few options used to look like this: > > ``` > https://lemmy.ml/home/data_type/Post/listing_type/All/sort/Active/page/1 > ``` > > The new route would look like this: > > ``` > https://lemmy.ml?listingType=All > ``` > Note that you now only have to specify parameters you want instead of all of them. > > #### Searchable select redesign > The searchable selects, such as those used on the search page, have a new look and feel. No more inexplicable green selects when using the lightly themes! > > #### Share button > > Posts on the web client now have a share button on supported browsers. This can be used to share posts to other applications quickly and easily. > > #### Lemmy-UI Overall look and feel > > lemmy-ui is now upgraded to bootstrap 5, and every component is now much cleaner. > > Special thanks to [sleepless](https://github.com/SleeplessOne1917), [alectrocute](https://github.com/alectrocute), [jsit](https://github.com/jsit), and many others for their great work on improving and re-organizing lemmy-ui. > > #### Database optimizations > > Special thanks to [johanndt](https://github.com/johanndt), for suggesting improvements to Lemmy's database queries. Some of these suggestions have already been implemented, and more are on the way. > > Query speed is Lemmy's main performance bottleneck, so we really appreciate any help database experts can provide. > > #### Captchas > > Captchas are not available in this version, as they need to be reimplemented in a different way. They will be back in 0.18.1, so wait with upgrading if you rely on them. > > ## Upgrade instructions > > Follow the upgrade instructions for [ansible](https://github.com/LemmyNet/lemmy-ansible#upgrading) or [docker](https://join-lemmy.org/docs/en/administration/install_docker.html#updating). > > If you need help with the upgrade, you can ask in our [support forum](https://lemmy.ml/c/lemmy_support) or on the [Matrix Chat](https://matrix.to/#/!OwmdVYiZSXrXbtCNLw:matrix.org). > > ## Support development > > We (@dessalines and @nutomic) have been working full-time on Lemmy for almost three years. This is largely thanks to support from [NLnet foundation](https://nlnet.nl/). > > If you like using Lemmy, and want to make sure that we will always be available to work full time building it, consider [donating to support its development](https://join-lemmy.org/donate). No one likes recurring donations, but they've proven to be the only way that open-source software like Lemmy can stay independent and alive. >

Anyone with experience using NixOS to create a Lemmy instance, please share any caveats and troubleshooting tips you have.