Help understanding cider installation problem

[Jim_Newton]

I’m just trying to install cider (emacs package) to start playing with Clojure. I’m a long time emacs user (30+years). When I attempt M-x package-install cider, I get the following stack trace.
When I take a look at the list of packages on melpa, I indeed see that clojure-mode-5.10.0.el is missing, but there is a 5.11.0.el available.

Debugger entered--Lisp error: (file-error "http://stable.melpa.org/packages/clojure-mode-5.10.0.el" "Not found")
  signal(file-error ("http://stable.melpa.org/packages/clojure-mode-5.10.0.el" "Not found"))
  package-install-from-archive(#s(package-desc :name clojure-mode :version (5 10 0) :summary "Major mode for Clojure code" :reqs ((emacs (25 1))) :kind single :archive "melpa-stable" :dir nil :extras ((:commit . "1ccef7b2b7a063aa42416d1518e8e7228d90a78d") (:keywords "languages" "clojure" "clojurescript" "lisp") (:url . "http://github.com/clojure-emacs/clojure-mode")) :signed nil))
  mapc(package-install-from-archive (#s(package-desc :name clojure-mode :version (5 10 0) :summary "Major mode for Clojure code" :reqs ((emacs (25 1))) :kind single :archive "melpa-stable" :dir nil :extras ((:commit . "1ccef7b2b7a063aa42416d1518e8e7228d90a78d") (:keywords "languages" "clojure" "clojurescript" "lisp") (:url . "http://github.com/clojure-emacs/clojure-mode")) :signed nil) #s(package-desc :name cider :version (0 20 0) :summary "Clojure Interactive Development Environment that Rocks" :reqs ((emacs (25)) (clojure-mode (5 9)) (pkg-info (0 4)) (queue (0 2)) (spinner (1 7)) (seq (2 16)) (sesman (0 3 2))) :kind tar :archive "melpa-stable" :dir nil :extras ((:commit . "702a60dfcdd11e7ec3104a7a6994be00fce7f200") (:keywords "languages" "clojure" "cider") (:authors ("Tim King" . "kingtim@gmail.com") ("Phil Hagelberg" . "technomancy@gmail.com") ("Bozhidar Batsov" . "bozhidar@batsov.com") ("Artur Malabarba" . "bruce.connor.am@gmail.com") ("Hugo Duncan" . "hugo@hugoduncan.org") ("Steve Purcell" . "steve@sanityinc.com")) (:maintainer "Bozhidar Batsov" . "bozhidar@batsov.com") (:url . "http://www.github.com/clojure-emacs/cider")) :signed nil)))
  package-download-transaction((#s(package-desc :name clojure-mode :version (5 10 0) :summary "Major mode for Clojure code" :reqs ((emacs (25 1))) :kind single :archive "melpa-stable" :dir nil :extras ((:commit . "1ccef7b2b7a063aa42416d1518e8e7228d90a78d") (:keywords "languages" "clojure" "clojurescript" "lisp") (:url . "http://github.com/clojure-emacs/clojure-mode")) :signed nil) #s(package-desc :name cider :version (0 20 0) :summary "Clojure Interactive Development Environment that Rocks" :reqs ((emacs (25)) (clojure-mode (5 9)) (pkg-info (0 4)) (queue (0 2)) (spinner (1 7)) (seq (2 16)) (sesman (0 3 2))) :kind tar :archive "melpa-stable" :dir nil :extras ((:commit . "702a60dfcdd11e7ec3104a7a6994be00fce7f200") (:keywords "languages" "clojure" "cider") (:authors ("Tim King" . "kingtim@gmail.com") ("Phil Hagelberg" . "technomancy@gmail.com") ("Bozhidar Batsov" . "bozhidar@batsov.com") ("Artur Malabarba" . "bruce.connor.am@gmail.com") ("Hugo Duncan" . "hugo@hugoduncan.org") ("Steve Purcell" . "steve@sanityinc.com")) (:maintainer "Bozhidar Batsov" . "bozhidar@batsov.com") (:url . "http://www.github.com/clojure-emacs/cider")) :signed nil)))
  package-install(cider nil)
  funcall-interactively(package-install cider nil)
  call-interactively(package-install record nil)
  command-execute(package-install record)
  execute-extended-command(nil "package-install" "package-inst")
  funcall-interactively(execute-extended-command nil "package-install" "package-inst")
  call-interactively(execute-extended-command nil nil)
  command-execute(execute-extended-command)

[Jim_Newton]

Answered my own question:

I simply needed to do a M-x package-refresh-contents, which updated the version pointer to 5.11.0.el