diff --git a/packages/py-nestml/package.py b/packages/py-nestml/package.py
index 7e3329d55ce4e0f73848a1b3d955cb1381d3f16a..d2010ea07dbcf620d6ea4dba35fe2b1ecd9ef478 100644
--- a/packages/py-nestml/package.py
+++ b/packages/py-nestml/package.py
@@ -18,6 +18,7 @@ class PyNestml(PythonPackage):
 
     maintainers = ['clinssen', 'pnbabu', 'jougs']
 
+    version('6.0.0', sha256='224993f175b9599a3662e65afdaf57e355246c0eab5f88b795fdb089ea28b39e', expand=False)
     version('5.3.0', sha256='8de543d7d3a166cd4d6a0d536a2d4e769513bbf8d7aeaf64458e9d9c21fe546e', expand=False)
     version('5.2.0', sha256='acb703bf9c7f70304bd5d547dccd6a6a219f8acb298a6412df779b808241eb14', expand=False)
 
diff --git a/packages/py-odetoolbox/package.py b/packages/py-odetoolbox/package.py
index 0f8265d12e9b20c65d3842d23aac1689bde53976..afb8fe4c869b776c1d338950443c6f26379e6a18 100644
--- a/packages/py-odetoolbox/package.py
+++ b/packages/py-odetoolbox/package.py
@@ -12,6 +12,7 @@ class PyOdetoolbox(PythonPackage):
 
     maintainers = ['clinssen']
 
+    version('2.5.4', sha256='eadb8f42a553cb34180a11d96cbac49ec4d0f07caf0358e066ab63415746e009', expand=False)
     version('2.5', sha256='947bbb289830dde60066106f5f628de2598a71129eafff8ec86317a0b5e8960e', expand=False)
 
     depends_on('python@3.8:', type=('build', 'run'))
@@ -20,7 +21,6 @@ class PyOdetoolbox(PythonPackage):
     depends_on('py-scipy', type=('build', 'run'))
     depends_on('py-numpy@1.8.2:', type=('build', 'run'))
     depends_on('py-cython', type=('build', 'run'))
-    depends_on('py-graphviz', type=('build', 'run'))
     depends_on('py-matplotlib', type=('build', 'run'))
     depends_on('py-setuptools', type=('build', 'run'))
     depends_on('py-pytest', type='test')
diff --git a/spack.yaml b/spack.yaml
index 94e3dbd67e5ca3c6dd3720347b7e1b58fe53961c..f599072f2a3657293e578eb19d66e7e6028dbae3 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -33,7 +33,7 @@ spack:
     - py-lfpykit@0.5.1
     - py-libsonata@0.1.23
     - py-neo@0.12.0
-    - py-nestml@5.3.0
+    - py-nestml@6.0.0
     - py-netpyne@1.0.5
     - py-neurom@3.2.2
     - py-neuror@1.6.4