diff --git a/libreoffice.spec b/libreoffice.spec
index 328b990..6b734ca 100644
--- a/libreoffice.spec
+++ b/libreoffice.spec
@@ -121,13 +121,13 @@ BuildRequires:  dejavu-fonts
 BuildRequires:  doxygen >= 1.8.4
 # Dot is used by doxygen
 BuildRequires:  fdupes
-BuildRequires:  flex
+BuildRequires:  flex >= 2.6.0
 BuildRequires:  flute
 BuildRequires:  fontforge
 BuildRequires:  glm-devel
 # Needed for tests
 BuildRequires:  google-carlito-fonts
-BuildRequires:  gperf >= 3.0.0
+BuildRequires:  gperf >= 3.1.0
 BuildRequires:  graphviz
 BuildRequires:  hyphen-devel
 # genbrk binary is required