diff --git a/gnu/packages/gnuzilla.scm b/gnu/packages/gnuzilla.scm
index 1910a6d64c..5df9f1f47b 100644
--- a/gnu/packages/gnuzilla.scm
+++ b/gnu/packages/gnuzilla.scm
@@ -522,9 +522,9 @@ (define all-mozilla-locales
 ;; XXXX: Workaround 'snippet' limitations.
 (define computed-origin-method (@@ (guix packages) computed-origin-method))
 
-(define %icecat-base-version "115.8.0")
+(define %icecat-base-version "115.9.0")
 (define %icecat-version (string-append %icecat-base-version "-guix0-preview1"))
-(define %icecat-build-id "20240220000000") ;must be of the form YYYYMMDDhhmmss
+(define %icecat-build-id "20240319000000") ;must be of the form YYYYMMDDhhmmss
 
 ;; 'icecat-source' is a "computed" origin that generates an IceCat tarball
 ;; from the corresponding upstream Firefox ESR tarball, using the 'makeicecat'
@@ -544,12 +544,12 @@ (define icecat-source
                   "firefox-" upstream-firefox-version ".source.tar.xz"))
             (sha256
              (base32
-              "1slmp2v1q3my81z8kiym9rpxw5d9n4sn07v7hv99517w7vr8d05g"))))
+              "00r847l2j2wk20wf1plbnz2ifyqkvwqmaqwq6zknsqz6qmqk6fyv"))))
 
          ;; The upstream-icecat-base-version may be older than the
          ;; %icecat-base-version.
-         (upstream-icecat-base-version "115.8.0")
-         (gnuzilla-commit "7e2ff1ad7e03d2bfe0b2daf3f25961b06cab8848")
+         (upstream-icecat-base-version "115.9.0")
+         (gnuzilla-commit "d1dab742d12e2ffacae70733b14016287fc46613")
          (gnuzilla-source
           (origin
             (method git-fetch)
@@ -561,7 +561,7 @@ (define icecat-source
                                       (string-take gnuzilla-commit 8)))
             (sha256
              (base32
-              "1lv3vfqv0zb634gnvzb37fs04rb1jlrd2n1k51yjsvdznpqfpi1y"))))
+              "16z2l0fbbxpl2q80w9mx0x89cq82plkb45jpf172xah0k782akhd"))))
 
          ;; 'search-patch' returns either a valid file name or #f, so wrap it
          ;; in 'assume-valid-file-name' to avoid 'local-file' warnings.