diff --git a/scripts/lib/install-shellcheck b/scripts/lib/install-shellcheck
index 8ad7c338cf..6aba3c452e 100755
--- a/scripts/lib/install-shellcheck
+++ b/scripts/lib/install-shellcheck
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -eu
 
-version=0.5.0
+version=0.6.0
 
 if ! out="$(shellcheck --version 2>/dev/null)" || [[ "$out" != *"
 version: $version
diff --git a/tools/deploy-branch b/tools/deploy-branch
index 8b664cfd31..d4b7375cd1 100755
--- a/tools/deploy-branch
+++ b/tools/deploy-branch
@@ -8,7 +8,7 @@ function error_out {
 }
 
 status=$(git status --porcelain | grep -v '^??')
-[ ! -z "$status" ] && error_out "Working directory or index not clean"
+[ -n "$status" ] && error_out "Working directory or index not clean"
 
 old_ref=$(git rev-list --max-count=1 HEAD)
 branch=$1
diff --git a/version.py b/version.py
index bb537ad938..a98ff9081c 100644
--- a/version.py
+++ b/version.py
@@ -11,4 +11,4 @@ LATEST_RELEASE_ANNOUNCEMENT = "https://blog.zulip.org/2018/11/07/zulip-1-9-relea
 # Typically, adding a dependency only requires a minor version bump, and
 # removing a dependency requires a major version bump.
 
-PROVISION_VERSION = '26.17'
+PROVISION_VERSION = '26.18'