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+# Release 0.8 (2005-04-11)
+
+NOTE: the hashing scheme in Nix 0.8 changed (as detailed below). As a
+result, `nix-pull` manifests and channels built for Nix 0.7 and below
+will not work anymore. However, the Nix expression language has not
+changed, so you can still build from source. Also, existing user
+environments continue to work. Nix 0.8 will automatically upgrade the
+database schema of previous installations when it is first run.
+
+If you get the error message
+
+    you have an old-style manifest `/nix/var/nix/manifests/[...]'; please
+    delete it
+
+you should delete previously downloaded manifests:
+
+    $ rm /nix/var/nix/manifests/*
+
+If `nix-channel` gives the error message
+
+    manifest `http://catamaran.labs.cs.uu.nl/dist/nix/channels/[channel]/MANIFEST'
+    is too old (i.e., for Nix <= 0.7)
+
+then you should unsubscribe from the offending channel (`nix-channel
+--remove
+URL`; leave out `/MANIFEST`), and subscribe to the same URL, with
+`channels` replaced by `channels-v3` (e.g.,
+<http://catamaran.labs.cs.uu.nl/dist/nix/channels-v3/nixpkgs-unstable>).
+
+Nix 0.8 has the following improvements:
+
+  - The cryptographic hashes used in store paths are now 160 bits long,
+    but encoded in base-32 so that they are still only 32 characters
+    long (e.g.,
+    `/nix/store/csw87wag8bqlqk7ipllbwypb14xainap-atk-1.9.0`). (This is
+    actually a 160 bit truncation of a SHA-256 hash.)
+
+  - Big cleanups and simplifications of the basic store semantics. The
+    notion of “closure store expressions” is gone (and so is the notion
+    of “successors”); the file system references of a store path are now
+    just stored in the database.
+    
+    For instance, given any store path, you can query its closure:
+    
+        $ nix-store -qR $(which firefox)
+        ... lots of paths ...
+    
+    Also, Nix now remembers for each store path the derivation that
+    built it (the “deriver”):
+    
+        $ nix-store -qR $(which firefox)
+        /nix/store/4b0jx7vq80l9aqcnkszxhymsf1ffa5jd-firefox-1.0.1.drv
+    
+    So to see the build-time dependencies, you can do
+    
+        $ nix-store -qR $(nix-store -qd $(which firefox))
+    
+    or, in a nicer format:
+    
+        $ nix-store -q --tree $(nix-store -qd $(which firefox))
+    
+    File system references are also stored in reverse. For instance, you
+    can query all paths that directly or indirectly use a certain Glibc:
+    
+        $ nix-store -q --referrers-closure \
+            /nix/store/8lz9yc6zgmc0vlqmn2ipcpkjlmbi51vv-glibc-2.3.4
+
+  - The concept of fixed-output derivations has been formalised.
+    Previously, functions such as `fetchurl` in Nixpkgs used a hack
+    (namely, explicitly specifying a store path hash) to prevent changes
+    to, say, the URL of the file from propagating upwards through the
+    dependency graph, causing rebuilds of everything. This can now be
+    done cleanly by specifying the `outputHash` and `outputHashAlgo`
+    attributes. Nix itself checks that the content of the output has the
+    specified hash. (This is important for maintaining certain
+    invariants necessary for future work on secure shared stores.)
+
+  - One-click installation :-) It is now possible to install any
+    top-level component in Nixpkgs directly, through the web — see,
+    e.g., <http://catamaran.labs.cs.uu.nl/dist/nixpkgs-0.8/>. All you
+    have to do is associate `/nix/bin/nix-install-package` with the MIME
+    type `application/nix-package` (or the extension `.nixpkg`), and
+    clicking on a package link will cause it to be installed, with all
+    appropriate dependencies. If you just want to install some specific
+    application, this is easier than subscribing to a channel.
+
+  - `nix-store -r
+            PATHS` now builds all the derivations PATHS in parallel. Previously
+    it did them sequentially (though exploiting possible parallelism
+    between subderivations). This is nice for build farms.
+
+  - `nix-channel` has new operations `--list` and `--remove`.
+
+  - New ways of installing components into user environments:
+    
+      - Copy from another user environment:
+        
+            $ nix-env -i --from-profile .../other-profile firefox
+    
+      - Install a store derivation directly (bypassing the Nix
+        expression language entirely):
+        
+            $ nix-env -i /nix/store/z58v41v21xd3...-aterm-2.3.1.drv
+        
+        (This is used to implement `nix-install-package`, which is
+        therefore immune to evolution in the Nix expression language.)
+    
+      - Install an already built store path directly:
+        
+            $ nix-env -i /nix/store/hsyj5pbn0d9i...-aterm-2.3.1
+    
+      - Install the result of a Nix expression specified as a
+        command-line argument:
+        
+            $ nix-env -f .../i686-linux.nix -i -E 'x: x.firefoxWrapper'
+        
+        The difference with the normal installation mode is that `-E`
+        does not use the `name` attributes of derivations. Therefore,
+        this can be used to disambiguate multiple derivations with the
+        same name.
+
+  - A hash of the contents of a store path is now stored in the database
+    after a successful build. This allows you to check whether store
+    paths have been tampered with: `nix-store
+            --verify --check-contents`.
+
+  - Implemented a concurrent garbage collector. It is now always safe to
+    run the garbage collector, even if other Nix operations are
+    happening simultaneously.
+    
+    However, there can still be GC races if you use `nix-instantiate`
+    and `nix-store
+                    --realise` directly to build things. To prevent races, use the
+    `--add-root` flag of those commands.
+
+  - The garbage collector now finally deletes paths in the right order
+    (i.e., topologically sorted under the “references” relation), thus
+    making it safe to interrupt the collector without risking a store
+    that violates the closure invariant.
+
+  - Likewise, the substitute mechanism now downloads files in the right
+    order, thus preserving the closure invariant at all times.
+
+  - The result of `nix-build` is now registered as a root of the garbage
+    collector. If the `./result` link is deleted, the GC root disappears
+    automatically.
+
+  - The behaviour of the garbage collector can be changed globally by
+    setting options in `/nix/etc/nix/nix.conf`.
+    
+      - `gc-keep-derivations` specifies whether deriver links should be
+        followed when searching for live paths.
+    
+      - `gc-keep-outputs` specifies whether outputs of derivations
+        should be followed when searching for live paths.
+    
+      - `env-keep-derivations` specifies whether user environments
+        should store the paths of derivations when they are added (thus
+        keeping the derivations alive).
+
+  - New `nix-env` query flags `--drv-path` and `--out-path`.
+
+  - `fetchurl` allows SHA-1 and SHA-256 in addition to MD5. Just specify
+    the attribute `sha1` or `sha256` instead of `md5`.
+
+  - Manual updates.