Fix typo.
diff --git a/INSTALL b/INSTALL
index e25adeb..9613233 100644
--- a/INSTALL
+++ b/INSTALL
@@ -9,7 +9,7 @@
 You will need working installations of Zlib and libcrypto (LibreSSL /
 OpenSSL)
 
-Zlib 1.1.4 or 1.2.1.2 or greater (ealier 1.2.x versions have problems):
+Zlib 1.1.4 or 1.2.1.2 or greater (earlier 1.2.x versions have problems):
 http://www.gzip.org/zlib/
 
 libcrypto (LibreSSL or OpenSSL >= 0.9.8f < 1.1.0)