diff --git a/cmake/Modules/Packages/PLUMED.cmake b/cmake/Modules/Packages/PLUMED.cmake
index b1a4f3cc72..562379eb78 100644
--- a/cmake/Modules/Packages/PLUMED.cmake
+++ b/cmake/Modules/Packages/PLUMED.cmake
@@ -21,9 +21,9 @@ else()
   set(PLUMED_CONFIG_OMP "--disable-openmp")
 endif()
 
-set(PLUMED_URL "https://github.com/plumed/plumed2/releases/download/v2.8.3/plumed-src-2.8.3.tgz"
+set(PLUMED_URL "https://github.com/plumed/plumed2/releases/download/v2.9.1/plumed-src-2.9.1.tgz"
   CACHE STRING "URL for PLUMED tarball")
-set(PLUMED_MD5 "76d23cd394eba9e6530316ed1184e219" CACHE STRING "MD5 checksum of PLUMED tarball")
+set(PLUMED_MD5 "c3b2d31479c1e9ce211719d40e9efbd7" CACHE STRING "MD5 checksum of PLUMED tarball")
 
 mark_as_advanced(PLUMED_URL)
 mark_as_advanced(PLUMED_MD5)
diff --git a/lib/plumed/Install.py b/lib/plumed/Install.py
index 4a158cb31f..4713cf9196 100644
--- a/lib/plumed/Install.py
+++ b/lib/plumed/Install.py
@@ -17,7 +17,7 @@ parser = ArgumentParser(prog='Install.py',
 
 # settings
 
-version = "2.8.3"
+version = "2.9.1"
 mode = "static"
 
 # help message
@@ -46,7 +46,9 @@ checksums = { \
         '2.8.1' : '6bfe72ebdae63dc38a9ca27d9b0e08f8', \
         '2.8.2' : '599092b6a0aa6fff992612537ad98994', \
         '2.8.3' : '76d23cd394eba9e6530316ed1184e219', \
+        '2.8.4' : '9f59c4f9bda86fe5bef19543c295a981', \
         '2.9.0' : '661eabeebee05cf84bbf9dc23d7d5f46', \
+        '2.9.1' : 'c3b2d31479c1e9ce211719d40e9efbd7', \
         }
 
 # parse and process arguments