diff --git a/powershell/Dockerfile b/powershell/Dockerfile
index c52f325..6ecdbc8 100644
--- a/powershell/Dockerfile
+++ b/powershell/Dockerfile
@@ -1,7 +1,7 @@
 FROM ubuntu:16.04
 LABEL maintainer "Christian Koep <christiankoep@gmail.com>"
 
-ENV POWERSHELL_VERSION v6.1.0-preview.1
+ENV POWERSHELL_VERSION 6.1.0-preview.1
 
 RUN apt-get update && apt-get install -y \
 	ca-certificates \
@@ -16,7 +16,7 @@ RUN apt-get update && apt-get install -y \
 	&& rm -rf /var/lib/apt/lists/*
 
 RUN cd /usr/src \
-	&& curl -L -O https://github.com/PowerShell/PowerShell/releases/download/v${POWERSHELL_VERSION}/powershell_${POWERSHELL_VERSION}-1.ubuntu.16.04_amd64.deb \
+	&& curl -L -O "https://github.com/PowerShell/PowerShell/releases/download/v${POWERSHELL_VERSION}/powershell_${POWERSHELL_VERSION}-1.ubuntu.16.04_amd64.deb" \
 	&& dpkg -i powershell_${POWERSHELL_VERSION}-1.ubuntu.16.04_amd64.deb \
 	&& apt-get install -fy \
 	&& rm -rf /var/lib/apt/lists/* /usr/src/*