diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2582c53a4..39b332a17 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
       run: make REDIS_CFLAGS='-Werror' BUILD_TLS=yes
     - name: test
       run: |
-        sudo apt-get install tcl8.5
+        sudo apt-get install tcl8.6
         ./runtest --verbose
     - name: module api test
       run: ./runtest-moduleapi --verbose
diff --git a/.github/workflows/daily.yml b/.github/workflows/daily.yml
index e3cb1a344..0a899d174 100644
--- a/.github/workflows/daily.yml
+++ b/.github/workflows/daily.yml
@@ -20,7 +20,7 @@ jobs:
       run: make
     - name: test
       run: |
-        sudo apt-get install tcl8.5
+        sudo apt-get install tcl8.6
         ./runtest --accurate --verbose --dump-logs
     - name: module api test
       run: ./runtest-moduleapi --verbose
@@ -39,7 +39,7 @@ jobs:
       run: make MALLOC=libc
     - name: test
       run: |
-        sudo apt-get install tcl8.5
+        sudo apt-get install tcl8.6
         ./runtest --accurate --verbose --dump-logs
     - name: module api test
       run: ./runtest-moduleapi --verbose
@@ -60,7 +60,7 @@ jobs:
         make 32bit
     - name: test
       run: |
-        sudo apt-get install tcl8.5
+        sudo apt-get install tcl8.6
         ./runtest --accurate --verbose --dump-logs
     - name: module api test
       run: |
@@ -82,7 +82,7 @@ jobs:
         make BUILD_TLS=yes
     - name: test
       run: |
-        sudo apt-get install tcl8.5 tcl-tls
+        sudo apt-get install tcl8.6 tcl-tls
         ./utils/gen-test-certs.sh
         ./runtest --accurate --verbose --tls --dump-logs
         ./runtest --accurate --verbose --dump-logs
@@ -110,7 +110,7 @@ jobs:
         make
     - name: test
       run: |
-        sudo apt-get install tcl8.5 tcl-tls
+        sudo apt-get install tcl8.6 tcl-tls
         ./runtest --config io-threads 4 --config io-threads-do-reads yes --accurate --verbose --tags network --dump-logs
     - name: cluster tests
       run: |
@@ -127,7 +127,7 @@ jobs:
     - name: test
       run: |
         sudo apt-get update
-        sudo apt-get install tcl8.5 valgrind -y
+        sudo apt-get install tcl8.6 valgrind -y
         ./runtest --valgrind --verbose --clients 1 --dump-logs
     - name: module api test
       run: ./runtest-moduleapi --valgrind --verbose --clients 1