diff --git a/.gitignore b/.gitignore
index 5588931..7124615 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,7 @@
 tags
 *.cs
+
+# MADR
+/node_modules/
+/package-lock.json
+/package.json
diff --git a/connection.capnp b/connection.capnp
index 6ec6ad9..95349f2 100644
--- a/connection.capnp
+++ b/connection.capnp
@@ -11,13 +11,31 @@ using MachineSystem = import "machinesystem.capnp".MachineSystem;
 using UserSystem = import "usersystem.capnp".UserSystem;
 using PermissionSystem = import "permissionsystem.capnp".PermissionSystem;
 
+const apiVersionMajor :Int32  = 0;
+const apiVersionMinor :Int32  = 3;
+const apiVersionPatch :Int32  = 0;
+
+struct Version
+{
+    major @0 :Int32;
+    minor @1 :Int32;
+    patch @2 :Int32;
+}
+
 interface Bootstrap 
 {
-    authenticationSystem @0 () -> ( authenticationSystem : AuthenticationSystem );
+    getAPIVersion @0 () -> ( version : Version );
 
-    machineSystem @1 () -> ( machineSystem : MachineSystem );
+    getServerRelease @1 () -> ( name :Text, release :Text );
+    # Returns the server implementation name and version/build number
+    # Designed only for human-facing debugging output so should be informative over machine-readable
+    # Example: ( name = "bffhd", release = "0.3.1-f397e1e [rustc 1.57.0 (f1edd0429 2021-11-29)]")
+
+    authenticationSystem @2 () -> ( authenticationSystem : AuthenticationSystem );
+
+    machineSystem @3 () -> ( machineSystem : MachineSystem );
     
-    userSystem @2 () -> ( userSystem : UserSystem );
+    userSystem @4 () -> ( userSystem : UserSystem );
 
-    permissionSystem @3 () -> ( permissionSystem : PermissionSystem );    
+    permissionSystem @5 () -> ( permissionSystem : PermissionSystem );
 }
diff --git a/docs/decisions/0000-use-markdown-architectural-decision-records.md b/docs/decisions/0000-use-markdown-architectural-decision-records.md
new file mode 100644
index 0000000..428218e
--- /dev/null
+++ b/docs/decisions/0000-use-markdown-architectural-decision-records.md
@@ -0,0 +1,22 @@
+# Use Markdown Architectural Decision Records (MADR)
+
+## Context and Problem Statement
+
+We want to record architectural decisions made in this project.
+Which format and structure should these records follow?
+
+## Considered Options
+
+* [Markdown Architectural Decisions Record (MADR)](https://adr.github.io/madr/)
+* Gitlab issues
+* Formless – No conventions for file format and structure
+
+## Decision Outcome
+
+Chosen option: "Markdown Architectural Decisions Record (MADR)", because
+
+* Markdown is an easy to write textual format requiring no tooling to be easily human readable
+* Markdown is widely supported and is auto-rendered by all git hosting platforms considered
+* Can be easily stored alongside the actual code and documentation since plain-text files play well with git
+* Is not bound to a single hosting platform like Gitlab issues would be
+* Gives a very sensible default template and format for us to use
diff --git a/docs/decisions/0001-require-strong-transport-encryption.md b/docs/decisions/0001-require-strong-transport-encryption.md
new file mode 100644
index 0000000..4fb9c57
--- /dev/null
+++ b/docs/decisions/0001-require-strong-transport-encryption.md
@@ -0,0 +1,92 @@
+# Require the use of transport encryption
+
+* Status: accepted <!-- optional -->
+* Deciders: @dequbed, @TheJoKlLa, @kjkriegel <!-- optional -->
+
+## Context and Problem Statement
+
+Implementers of the API should use some level of transport encryption for any
+non-local communication because it's not the 2000's anymore and our crypto is
+actually good, cheap and secure.
+
+## Decision Drivers <!-- optional -->
+
+* The software stack in question has a decent amount of security relevance, even when only used in a LAN context.
+* Since most users of the API connect via WLAN and most of those are using PSK, eavesdropping is trivial
+
+## Considered Options
+
+* [TLS]
+* [DTLS]
+* [Noise protocol][noise]
+
+## Decision Outcome
+
+Chosen option: "TLS", because TLS overall is the easiest to implement for the
+remaining stack as it currently stands and most sysadmins have a good
+understanding of the PKI of TLS.
+
+### Positive Consequences <!-- optional -->
+
+* Reliable transport encryption is ensured
+* PKI structure of TLS can easily solve the inherent trust establishment problem in a federated setting
+
+### Negative Consequences <!-- optional -->
+
+* Generating a trusted X.509 certificate is required for federated application incurring either monetary cost or additional setup work
+* Encryption overhead is a relevant factor in ultra-low-powered devices in cases with a for that use-case badly configured server (i.e. not offering ChaCha20 and other computationally cheap algorithms)
+
+## Pros and Cons of the Options <!-- optional -->
+
+### TLS
+
+Use the known and proven TLS protocol <!-- optional -->
+
+* Good, because TLS support is ubiquitous on all platforms
+* Good, because TLS allows to negotiate cipher algorithms allowing different devices to chose the cipher best suited for them
+* Good, because TLS offers extensions, e.g. [ALPN] that make protocol versioning easier
+* Bad, because TLS is not well suited for [SCTP] which the protocol in future wants to switch to
+* Bad, because TLS is inherently very complex and has suffered from many attack vectors, best known e.g. [Heartbleed] and [Logjam] that require extra caution when configuring TLS
+* Bad, because TLS' cipher negotiation (especially below version 1.3) is susceptible to downgrade attacks, especially in the case of a `STARTTLS`-style usage.
+
+### DTLS
+
+Use the [Datagram Transport Layer Security][DTLS] which is an IETF protocol similar to TLS but specifically designed for message-orientated protocols where message losses and reoderings have to be tolerated.
+
+* Good, because it shares most of the advantages of TLS but also [more ergonomically works with SCTP][sctp-dtls]
+* Bad, because DTLS is significantly less well supported than TLS
+* Bad, because DTLS has no equivalent for TLSv1.3 which adds significant improvents over TLSv1.2 in terms of security
+
+### Noise protocol framework
+
+Use encryption based on Noise, a framework with support for mutual and optional authentication, identity hiding, forward secrecy, zero round-trip encryption, and other advanced features. <!-- optional -->
+
+* Good, because it has no design for cipher negotiation making downgrade attacks impossible
+* Good, because the lightweight nature of noise and the ciphers chosen means it has very limited impact compared to TLS or DTLS
+* Good, because noise lends itself very well to a system where encryption keys are shared via side-channel, e.g. by scanning a QR code also containing the address to connect to.
+* Bad, because platform support is very limited compared to TLS/DTLS, although the most important ones i.e. [Rust][noise-rust] (bffhd), [C#](noise-csharp) (Borepin), Python([1][noise-python1], [2][noise-python2]) (pyfabaccess) are covered.
+* Bad, because noise requires more implementation work than TLS in terms of numbers of lines of code and in decisions to make.
+
+## Links <!-- optional -->
+
+* [Transport Layer Security (TLS)][TLS]
+* [Datagram Transport Layer Security (DTLS)][DTLS]
+* [Noise Protocol Framework][noise]
+* [TLS Application-Layer Protocol Negotiation Extension (ALPN)][ALPN]
+* [Stream Control Transmission Protocol (SCTP)][SCTP]
+* [Heartbleed]
+* [LogJam]
+* [Datagram Transport Layer Security for Stream Control Transmission Protocol][sctp-dtls]
+
+[TLS]: https://en.wikipedia.org/wiki/Transport_Layer_Security
+[DTLS]: https://en.wikipedia.org/wiki/Datagram_Transport_Layer_Security
+[noise]: http://www.noiseprotocol.org/
+[ALPN]: https://datatracker.ietf.org/doc/html/rfc7301
+[SCTP]: https://en.wikipedia.org/wiki/Stream_Control_Transmission_Protocol
+[Heartbleed]: https://heartbleed.com/
+[LogJam]: https://weakdh.org/logjam.html
+[sctp-dtls]: https://datatracker.ietf.org/doc/html/rfc6083
+[noise-rust]: https://github.com/mcginty/snow
+[noise-csharp]: https://github.com/Metalnem/noise
+[noise-python1]: https://github.com/plizonczyk/noiseprotocol
+[noise-python2]: https://github.com/tgalal/dissononce
diff --git a/docs/decisions/index.md b/docs/decisions/index.md
new file mode 100644
index 0000000..2ab5d0c
--- /dev/null
+++ b/docs/decisions/index.md
@@ -0,0 +1,14 @@
+# Architectural Decision Log
+
+This log lists the architectural decisions for [project name].
+
+<!-- adrlog -- Regenerate the content by using "adr-log -i". You can install it via "npm install -g adr-log" -->
+
+* [ADR-0000](0000-use-markdown-architectural-decision-records.md) - Use Markdown Architectural Decision Records (MADR)
+* [ADR-0001](0001-require-strong-transport-encryption.md) - Require the use of transport encryption
+
+<!-- adrlogstop -->
+
+For new ADRs, please use [template.md](template.md) as basis.
+More information on MADR is available at <https://adr.github.io/madr/>.
+General information about architectural decision records is available at <https://adr.github.io/>.
diff --git a/docs/decisions/template.md b/docs/decisions/template.md
new file mode 100644
index 0000000..25696bb
--- /dev/null
+++ b/docs/decisions/template.md
@@ -0,0 +1,72 @@
+# [short title of solved problem and solution]
+
+* Status: [proposed | rejected | accepted | deprecated | … | superseded by [ADR-0005](0005-example.md)] <!-- optional -->
+* Deciders: [list everyone involved in the decision] <!-- optional -->
+* Date: [YYYY-MM-DD when the decision was last updated] <!-- optional -->
+
+Technical Story: [description | ticket/issue URL] <!-- optional -->
+
+## Context and Problem Statement
+
+[Describe the context and problem statement, e.g., in free form using two to three sentences. You may want to articulate the problem in form of a question.]
+
+## Decision Drivers <!-- optional -->
+
+* [driver 1, e.g., a force, facing concern, …]
+* [driver 2, e.g., a force, facing concern, …]
+* … <!-- numbers of drivers can vary -->
+
+## Considered Options
+
+* [option 1]
+* [option 2]
+* [option 3]
+* … <!-- numbers of options can vary -->
+
+## Decision Outcome
+
+Chosen option: "[option 1]", because [justification. e.g., only option, which meets k.o. criterion decision driver | which resolves force force | … | comes out best (see below)].
+
+### Positive Consequences <!-- optional -->
+
+* [e.g., improvement of quality attribute satisfaction, follow-up decisions required, …]
+* …
+
+### Negative Consequences <!-- optional -->
+
+* [e.g., compromising quality attribute, follow-up decisions required, …]
+* …
+
+## Pros and Cons of the Options <!-- optional -->
+
+### [option 1]
+
+[example | description | pointer to more information | …] <!-- optional -->
+
+* Good, because [argument a]
+* Good, because [argument b]
+* Bad, because [argument c]
+* … <!-- numbers of pros and cons can vary -->
+
+### [option 2]
+
+[example | description | pointer to more information | …] <!-- optional -->
+
+* Good, because [argument a]
+* Good, because [argument b]
+* Bad, because [argument c]
+* … <!-- numbers of pros and cons can vary -->
+
+### [option 3]
+
+[example | description | pointer to more information | …] <!-- optional -->
+
+* Good, because [argument a]
+* Good, because [argument b]
+* Bad, because [argument c]
+* … <!-- numbers of pros and cons can vary -->
+
+## Links <!-- optional -->
+
+* [Link type] [Link to ADR] <!-- example: Refined by [ADR-0005](0005-example.md) -->
+* … <!-- numbers of links can vary -->
diff --git a/machine.capnp b/machine.capnp
index 2b31750..38254fe 100644
--- a/machine.capnp
+++ b/machine.capnp
@@ -38,6 +38,7 @@ struct Machine {
     manager @5:User;
     wiki @13 :Text;
     urn @14 :Text;
+    category @15 :Text;
 
     info @6 :Info;
     interface Info $CSharp.name("InfoInterface") {