diff --git a/var/spack/repos/builtin/packages/py-unicycler/package.py b/var/spack/repos/builtin/packages/py-unicycler/package.py
index 16789a83cf..9fd64c0e4a 100644
--- a/var/spack/repos/builtin/packages/py-unicycler/package.py
+++ b/var/spack/repos/builtin/packages/py-unicycler/package.py
@@ -17,19 +17,27 @@ class PyUnicycler(PythonPackage):
     homepage = "https://github.com/rrwick/Unicycler"
     url      = "https://github.com/rrwick/Unicycler/archive/v0.4.5.tar.gz"
 
+    version('0.5.0', sha256='84a8709c9f2e624225410af702d779ffb0cb06f7c22c20e1f01b989945e08a47')
+    version('0.4.9', sha256='84bea8f3e8f99a1e63e5230ffe474a696db8caa67569c3a96ae12906d32a35eb')
+    version('0.4.8', sha256='e948871e4de9db5964c9ca6f8f877c3cbe6a46f62052dfab52ffe0f45bbbd203')
     version('0.4.7', sha256='a8cf65e46dc2694b0fbd4e9190c73a1f300921457aadfab27a1792b785620d63')
     version('0.4.6', sha256='56f6f358a5d1f8dd0fcd1df04504079fc42cec8453a36ee59ff89295535d03f5')
     version('0.4.5', sha256='67043656b31a4809f8fa8f73368580ba7658c8440b9f6d042c7f70b5eb6b19ae')
 
     depends_on('python@3.4:', type=('build', 'link', 'run'))
     depends_on('py-setuptools', type=('build', 'run'))
-    depends_on('spades', type='run')
-    depends_on('pilon', type='run')
-    depends_on('jdk', type=('build', 'run'))
-    depends_on('bowtie2', type='run')
-    depends_on('samtools@1.0:', type=('build', 'link', 'run'))
     depends_on('racon', type=('build', 'link', 'run'))
     depends_on('blast-plus', type='run')
 
+    # for version 0.5.0
+    depends_on('spades@3.14.0:', type='run', when='@0.5.0')
+
+    # for versions 0.4.9 and earlier
+    depends_on('spades@3.6.2:3.13.0', type='run', when='@:0.4.9')
+    depends_on('pilon', type='run', when='@:0.4.9')
+    depends_on('java', type=('build', 'run'), when='@:0.4.9')
+    depends_on('bowtie2', type='run', when='@:0.4.9')
+    depends_on('samtools@1.0:', type=('build', 'link', 'run'), when='@:0.4.9')
+
     conflicts('%gcc@:4.9.0')
     conflicts('%clang@:3.4.2')