diff --git a/doc/Changelog.md b/doc/Changelog.md
index c9878bba..999d1bb3 100644
--- a/doc/Changelog.md
+++ b/doc/Changelog.md
@@ -6,7 +6,8 @@ LameXP Audio-Encoder Front-End – Changelog
 # LameXP v4.xx History #
 
 ## LameXP v4.16 [UNRELEASED] ## {-}
-* Updated Opus encoder/decoder libraries to v1.2-RC1 (2017-06-06) and Opus-Tools to v0.1.10 (2017-05-25)
+* Upgraded build environment to Microsoft Visual Studio 2017 with Update-2
+* Updated Opus encoder/decoder libraries to v1.2.1 (2017-07-26) and Opus-Tools to v0.1.10 (2017-05-25)
 
 ## LameXP v4.15 [2017-05-31] ## {-}
 
diff --git a/res/tools/opusdec.avx.exe b/res/tools/opusdec.avx.exe
index 7b60314b..8b3418f1 100644
Binary files a/res/tools/opusdec.avx.exe and b/res/tools/opusdec.avx.exe differ
diff --git a/res/tools/opusdec.i686.exe b/res/tools/opusdec.i686.exe
index 9dc33f30..eb101ce7 100644
Binary files a/res/tools/opusdec.i686.exe and b/res/tools/opusdec.i686.exe differ
diff --git a/res/tools/opusdec.sse2.exe b/res/tools/opusdec.sse2.exe
index 289466d9..7715e9d1 100644
Binary files a/res/tools/opusdec.sse2.exe and b/res/tools/opusdec.sse2.exe differ
diff --git a/res/tools/opusenc.avx.exe b/res/tools/opusenc.avx.exe
index 3c6f500b..c93910aa 100644
Binary files a/res/tools/opusenc.avx.exe and b/res/tools/opusenc.avx.exe differ
diff --git a/res/tools/opusenc.i686.exe b/res/tools/opusenc.i686.exe
index 7eb3cd6e..9821e7d9 100644
Binary files a/res/tools/opusenc.i686.exe and b/res/tools/opusenc.i686.exe differ
diff --git a/res/tools/opusenc.sse2.exe b/res/tools/opusenc.sse2.exe
index d1faa447..1b15812b 100644
Binary files a/res/tools/opusenc.sse2.exe and b/res/tools/opusenc.sse2.exe differ
diff --git a/src/Tools.h b/src/Tools.h
index ec98798a..baa309b0 100644
--- a/src/Tools.h
+++ b/src/Tools.h
@@ -98,12 +98,12 @@ g_lamexp_tools[] =
 	{"245181321625445ac42fce31d64bf03872e77e2d0dd3c19d6c17ca2771354f096a6040827dd6d00ffd7342c7dd26168e", CPU_TYPE_X86_GEN, "oggenc2.i686.exe", 288135603, "2015"},
 	{"512b8efcd1003a0f67220a450d6ea4466194e8fd49fc090a69b15a858db11499acbf98f984530cd5d37b4b6abdd1c6d8", CPU_TYPE_X86_SSX, "oggenc2.sse2.exe", 288135603, "2015"},
 	{"a07ef67cba5a00d335d07372baf76d4d0573b425afce71a19c1e04eaabbe3f55e60bdd40af5e428224c91df1823eda08", CPU_TYPE_X64_ALL, "oggenc2.x64.exe",  288135603, "2015"},
-	{"e461592d1ebd4d85b8743afb5689a3301d219680048e53345c02de8b44f6684cbb17bc57280767e101a904dfd6ebfb5b", CPU_TYPE_ALL_GEN, "opusdec.i686.exe", 20170506, "v1.2-rc1"},
-	{"b17e8f2b58d60e48371d9c4f51eeb8a2068d8eef3300bae8c1d4ded56b02519c62f36ee13594647cc88293acd8506fda", CPU_TYPE_ALL_SSE, "opusdec.sse2.exe", 20170506, "v1.2-rc1"},
-	{"50daa9ad7af20a6162d49f896e6cca382dab061ade68cbaa8d7a63d63a72248e8cac22fa28c3334cf567499d7419e1b8", CPU_TYPE_ALL_AVX, "opusdec.avx.exe",  20170506, "v1.2-rc1"},
-	{"91f0cb94ac54cbc151143d70d3abb28277ed8b0632fdd167fd75f496f993b12ef466217392dbe2a4dc778b6f6f466c1a", CPU_TYPE_ALL_GEN, "opusenc.i686.exe", 20170506, "v1.2-rc1"},
-	{"6e58761acd98687ed6dcff1d325831d1da0cd80585eff45a6d354f805b86b49a8a732dddcc21f667b141a8a792e55958", CPU_TYPE_ALL_SSE, "opusenc.sse2.exe", 20170506, "v1.2-rc1"},
-	{"68118837ba5c8c737803167f9d22a7937b501a59aa1061b3828a64fc66272905534029f5488a37d06769231f7a90ddbc", CPU_TYPE_ALL_AVX, "opusenc.avx.exe",  20170506, "v1.2-rc1"},
+	{"aff05e0b80e885a859803477fe128d969275fd563281edfe8ee3f3e5c810e7b0c8302f4d826e824756540a83c97714fd", CPU_TYPE_ALL_GEN, "opusdec.i686.exe", 20170726, "v1.2.1"},
+	{"15a963561b38b18436e4e633ccfa6515cc88e50977075d4fe89d8ccc3a16ee4dd34468734dda4f72fe771ff025eb2b36", CPU_TYPE_ALL_SSE, "opusdec.sse2.exe", 20170726, "v1.2.1"},
+	{"f641668bae226a4aee893a05ca3f7adc585191e3e33dcf461f56ab6ac9559aafe3a444889ce0a25b12cafd2d00df8dbc", CPU_TYPE_ALL_AVX, "opusdec.avx.exe",  20170726, "v1.2.1"},
+	{"c59ae1739ad39f139bb424a2417bf80abecd62333f8620ff8c9a20d9ec775a59e8350de47be21c52ace1ee72e9a94c54", CPU_TYPE_ALL_GEN, "opusenc.i686.exe", 20170726, "v1.2.1"},
+	{"8d3d6d14a48b94ca0760ef257702de4b841cb248d6a2f2356f0303026658e7697c3efcb2bbe6aaf650cc286519d7eddf", CPU_TYPE_ALL_SSE, "opusenc.sse2.exe", 20170726, "v1.2.1"},
+	{"32622397d421c56e2d832fb3c94751694ed98fc00e687e564d9093414d385ab64e73e158fbe3306e7a94ee6381c0c97c", CPU_TYPE_ALL_AVX, "opusenc.avx.exe",  20170726, "v1.2.1"},
 	{"37745174e146fedbc62671ab86ffddd3edfc9aa0ebfcfd4bff3331a95b6dda50621478c63f7a0ddf9a365e916758b6d4", CPU_TYPE_X86_ALL, "refalac.i686.exe", 161, ""},
 	{"b368f0490cefb80b6ff7eaaf8d6e29f253442375caf11a9405b5b21580ee3a9739fa3f406f69de5ef344fa038b1cbe72", CPU_TYPE_X64_ALL, "refalac.x64.exe",  161, ""},
 	{"d041b60de6c5c6e77cbad84440db57bbeb021af59dd0f7bebd3ede047d9e2ddc2a0c14179472687ba91063743d23e337", CPU_TYPE_ALL_ALL, "shorten.exe", 361, ""},