--- compat.h.orig	2020-10-05 10:09:02.953505129 -0700

+++ compat.h	2020-10-05 10:10:17.587733113 -0700

@@ -34,7 +34,7 @@

 #define SSH_BUG_UTF8TTYMODE	0x00000001

 #define SSH_BUG_SIGTYPE		0x00000002

-/* #define unused		0x00000004 */

+#define SSH_BUG_SIGTYPE74	0x00000004

 /* #define unused		0x00000008 */

 #define SSH_OLD_SESSIONID	0x00000010

 /* #define unused		0x00000020 */

--- compat.c.orig	2020-10-05 10:25:02.088720562 -0700

+++ compat.c	2020-10-05 10:13:11.637282492 -0700

@@ -65,11 +65,12 @@

 		{ "OpenSSH_6.5*,"

 		  "OpenSSH_6.6*",	SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD|

 					SSH_BUG_SIGTYPE},

+		{ "OpenSSH_7.4*",	SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE|

+		  			SSH_BUG_SIGTYPE74},

 		{ "OpenSSH_7.0*,"

 		  "OpenSSH_7.1*,"

 		  "OpenSSH_7.2*,"

 		  "OpenSSH_7.3*,"

-		  "OpenSSH_7.4*,"

 		  "OpenSSH_7.5*,"

 		  "OpenSSH_7.6*,"

 		  "OpenSSH_7.7*",	SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},

--- sshconnect2.c.orig	2020-09-26 07:26:37.618010545 -0700

+++ sshconnect2.c	2020-10-05 10:47:22.116315148 -0700

@@ -1305,6 +1305,26 @@

 			break;

 	}

 	free(oallowed);

+	/*

+	 * OpenSSH 7.4 supports SHA2 sig types, but fails to indicate its

+	 * support.  For that release, check the local policy against the

+	 * SHA2 signature types.

+	 */

+	if (alg == NULL &&

+	    (key->type == KEY_RSA && (datafellows & SSH_BUG_SIGTYPE74))) {

+		oallowed = allowed = xstrdup(options.pubkey_key_types);

+		while ((cp = strsep(&allowed, ",")) != NULL) {

+			if (sshkey_type_from_name(cp) != key->type)

+				continue;

+			tmp = match_list(sshkey_sigalg_by_name(cp), "rsa-sha2-256,rsa-sha2-512", NULL);

+			if (tmp != NULL)

+				alg = xstrdup(cp);

+			free(tmp);

+			if (alg != NULL)

+				break;

+		}

+		free(oallowed);

+	}

 	return alg;

 }