diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3bf09dd81c4c1fc5a14b3ca337fccb671eda2748..6e4dfb0d05434208217719788a8a786d1a53d14d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,23 +6,23 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 
-## [v0.5.1] - unreleased
+## [v0.5.1] - 13-06-2024
 
 ### Added
 
-- `core.logoutput` parameter to define whether logs are printed to screen, file, none, or both
+- Unitful.jl now used to add units to quantities
 
 - `world.mapdirectory` parameter specifies the path to the directory in which
  `landcovermap`, `farmfieldsmap`, and `weatherfile` are located
  
+- `world.mapresolution` parameter specifies the input maps' spatial resolution in meters
+ 
 ### Changed
 
-### Deprecated
-
-### Removed
-
-### Fixed
+- spatial functions now work with explicit distances (using Unitful.jl) rather than using
+  the number of pixels
 
+- all species definitions and tests updated to use units
 
 ## [v0.5.0] - 07-06-2024
 
@@ -43,7 +43,9 @@ way the species definition macros work and are used.
   - `directionto()`, `distanceto()`, `randomdirection()`
   - `nagents()`, `killallanimals!()`
 
-- `@here`
+- `@here` macro to return the pixel currently occupied by the active animal
+
+- `core.logoutput` parameter to define whether logs are printed to screen, file, none, or both
 
 - large logo and model structure diagram
 
diff --git a/Project.toml b/Project.toml
index cc9f1d5cd99a086dfa590f4a9d1908cd35f88ddf..12bc3cd5ed93d571d42db9c802d5ac6fd21f9c81 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "Persefone"
 uuid = "039acd1d-2a07-4b33-b082-83a1ff0fd136"
 authors = ["Daniel Vedder <daniel.vedder@idiv.de>"]
-version = "0.5.0"
+version = "0.5.1"
 
 [deps]
 ArgParse = "c7e460c6-2fb9-53a9-8c5b-16f535851c63"
@@ -24,6 +24,7 @@ StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 TOML = "fa267f1f-6049-4f14-aa54-33bafae1ed76"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 TiffImages = "731e570b-9d59-4bfa-96dc-6df516fadf69"
+Unitful = "1986cc42-f94f-5a68-af5c-568840ba703d"
 
 [compat]
 julia = ">= 1.10"
diff --git a/README.md b/README.md
index 8281283c3c2658036ab433add1087a29cefb0ba9..935fcfcb870a319c49022c1b03feb540151f9a92 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ growth submodel, and individual-based models of multiple indicator species. Its
 investigate how changes in farm operations (e.g. through policy changes in the CAP) 
 influence biodiversity.
 
-**The model is still in development. A first version will be available in spring 2024.**
+**The model is still in development. A first version will be available in summer 2024.**
 
 ## Usage