diff --git a/addons/xterm-addon-ligatures/package.json b/addons/xterm-addon-ligatures/package.json
index 2da54bb90e..df85c0204c 100644
--- a/addons/xterm-addon-ligatures/package.json
+++ b/addons/xterm-addon-ligatures/package.json
@@ -37,8 +37,8 @@
   "devDependencies": {
     "@types/sinon": "^5.0.1",
     "axios": "^0.18.0",
-    "mkdirp": "^0.5.1",
-    "sinon": "^6.1.3",
+    "mkdirp": "0.5.5",
+    "sinon": "6.3.5",
     "yauzl": "^2.10.0"
   },
   "peerDependencies": {
diff --git a/addons/xterm-addon-ligatures/yarn.lock b/addons/xterm-addon-ligatures/yarn.lock
index c170eb30ac..d8e64e495c 100644
--- a/addons/xterm-addon-ligatures/yarn.lock
+++ b/addons/xterm-addon-ligatures/yarn.lock
@@ -2,20 +2,49 @@
 # yarn lockfile v1
 
 
-"@sinonjs/formatio@^2.0.0":
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/@sinonjs/formatio/-/formatio-2.0.0.tgz#84db7e9eb5531df18a8c5e0bfb6e449e55e654b2"
+"@sinonjs/commons@^1", "@sinonjs/commons@^1.0.2", "@sinonjs/commons@^1.3.0", "@sinonjs/commons@^1.7.0":
+  version "1.8.0"
+  resolved "https://registry.yarnpkg.com/@sinonjs/commons/-/commons-1.8.0.tgz#c8d68821a854c555bba172f3b06959a0039b236d"
+  integrity sha512-wEj54PfsZ5jGSwMX68G8ZXFawcSglQSXqCftWX3ec8MDUzQdHgcKvw97awHbY0efQEL5iKUOAmmVtoYgmrSG4Q==
   dependencies:
-    samsam "1.3.0"
+    type-detect "4.0.8"
 
-"@sinonjs/samsam@^2.0.0":
-  version "2.0.0"
-  resolved "https://registry.yarnpkg.com/@sinonjs/samsam/-/samsam-2.0.0.tgz#9163742ac35c12d3602dece74317643b35db6a80"
+"@sinonjs/formatio@^3.0.0", "@sinonjs/formatio@^3.2.1":
+  version "3.2.2"
+  resolved "https://registry.yarnpkg.com/@sinonjs/formatio/-/formatio-3.2.2.tgz#771c60dfa75ea7f2d68e3b94c7e888a78781372c"
+  integrity sha512-B8SEsgd8gArBLMD6zpRw3juQ2FVSsmdd7qlevyDqzS9WTCtvF55/gAL+h6gue8ZvPYcdiPdvueM/qm//9XzyTQ==
+  dependencies:
+    "@sinonjs/commons" "^1"
+    "@sinonjs/samsam" "^3.1.0"
+
+"@sinonjs/samsam@^2.1.2":
+  version "2.1.3"
+  resolved "https://registry.yarnpkg.com/@sinonjs/samsam/-/samsam-2.1.3.tgz#62cf2a9b624edc795134135fe37fc2ae8ea36be3"
+  integrity sha512-8zNeBkSKhU9a5cRNbpCKau2WWPfan+Q2zDlcXvXyhn9EsMqgYs4qzo0XHNVlXC6ABQL8fT6nV+zzo5RTHJzyXw==
+
+"@sinonjs/samsam@^3.1.0":
+  version "3.3.3"
+  resolved "https://registry.yarnpkg.com/@sinonjs/samsam/-/samsam-3.3.3.tgz#46682efd9967b259b81136b9f120fd54585feb4a"
+  integrity sha512-bKCMKZvWIjYD0BLGnNrxVuw4dkWCYsLqFOUWw8VgKF/+5Y+mE7LfHWPIYoDXowH+3a9LsWDMo0uAP8YDosPvHQ==
+  dependencies:
+    "@sinonjs/commons" "^1.3.0"
+    array-from "^2.1.1"
+    lodash "^4.17.15"
+
+"@sinonjs/text-encoding@^0.7.1":
+  version "0.7.1"
+  resolved "https://registry.yarnpkg.com/@sinonjs/text-encoding/-/text-encoding-0.7.1.tgz#8da5c6530915653f3a1f38fd5f101d8c3f8079c5"
+  integrity sha512-+iTbntw2IZPb/anVDbypzfQa+ay64MW0Zo8aJ8gZPWMMK6/OubMVb6lUPMagqjOPnmtauXnFCACVl3O7ogjeqQ==
 
 "@types/sinon@^5.0.1":
   version "5.0.1"
   resolved "https://registry.yarnpkg.com/@types/sinon/-/sinon-5.0.1.tgz#a15b36ec42f1f53166617491feabd1734cb03e21"
 
+array-from@^2.1.1:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/array-from/-/array-from-2.1.1.tgz#cfe9d8c26628b9dc5aecc62a9f5d8f1f352c1195"
+  integrity sha1-z+nYwmYoudxa7MYqn12PHzUsEZU=
+
 axios@^0.18.0:
   version "0.18.1"
   resolved "https://registry.yarnpkg.com/axios/-/axios-0.18.1.tgz#ff3f0de2e7b5d180e757ad98000f1081b87bcea3"
@@ -81,17 +110,31 @@ isarray@0.0.1:
   version "0.0.1"
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-0.0.1.tgz#8a18acfca9a8f4177e09abfc6038939b05d1eedf"
 
-just-extend@^1.1.27:
-  version "1.1.27"
-  resolved "https://registry.yarnpkg.com/just-extend/-/just-extend-1.1.27.tgz#ec6e79410ff914e472652abfa0e603c03d60e905"
+just-extend@^4.0.2:
+  version "4.1.0"
+  resolved "https://registry.yarnpkg.com/just-extend/-/just-extend-4.1.0.tgz#7278a4027d889601640ee0ce0e5a00b992467da4"
+  integrity sha512-ApcjaOdVTJ7y4r08xI5wIqpvwS48Q0PBG4DJROcEkH1f8MdAiNFyFxz3xoL0LWAVwjrwPYZdVHHxhRHcx/uGLA==
 
 lodash.get@^4.4.2:
   version "4.4.2"
   resolved "https://registry.yarnpkg.com/lodash.get/-/lodash.get-4.4.2.tgz#2d177f652fa31e939b4438d5341499dfa3825e99"
 
-lolex@^2.3.2, lolex@^2.4.2:
-  version "2.7.1"
-  resolved "https://registry.yarnpkg.com/lolex/-/lolex-2.7.1.tgz#e40a8c4d1f14b536aa03e42a537c7adbaf0c20be"
+lodash@^4.17.15:
+  version "4.17.19"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.19.tgz#e48ddedbe30b3321783c5b4301fbd353bc1e4a4b"
+  integrity sha512-JNvd8XER9GQX0v2qJgsaN/mzFCNA5BRe/j8JN9d+tWyGLSodKQHKFicdwNYzWwI3wjRnaKPsGj1XkBjx/F96DQ==
+
+lolex@^2.7.5:
+  version "2.7.5"
+  resolved "https://registry.yarnpkg.com/lolex/-/lolex-2.7.5.tgz#113001d56bfc7e02d56e36291cc5c413d1aa0733"
+  integrity sha512-l9x0+1offnKKIzYVjyXU2SiwhXDLekRzKyhnbyldPHvC7BvLPVpdNUNR2KeMAiCN2D/kLNttZgQD5WjSxuBx3Q==
+
+lolex@^5.0.1:
+  version "5.1.2"
+  resolved "https://registry.yarnpkg.com/lolex/-/lolex-5.1.2.tgz#953694d098ce7c07bc5ed6d0e42bc6c0c6d5a367"
+  integrity sha512-h4hmjAvHTmd+25JSwrtTIuwbKdwg5NzZVRMLn9saij4SZaepCrTCxPr35H/3bjwfMJtN+t3CX8672UIkglz28A==
+  dependencies:
+    "@sinonjs/commons" "^1.7.0"
 
 lru-cache@^4.1.3:
   version "4.1.3"
@@ -100,29 +143,32 @@ lru-cache@^4.1.3:
     pseudomap "^1.0.2"
     yallist "^2.1.2"
 
-minimist@0.0.8:
-  version "0.0.8"
-  resolved "https://registry.yarnpkg.com/minimist/-/minimist-0.0.8.tgz#857fcabfc3397d2625b8228262e86aa7a011b05d"
+minimist@^1.2.5:
+  version "1.2.5"
+  resolved "https://registry.yarnpkg.com/minimist/-/minimist-1.2.5.tgz#67d66014b66a6a8aaa0c083c5fd58df4e4e97602"
+  integrity sha512-FM9nNUYrRBAELZQT3xeZQ7fmMOBg6nWNmJKTcgsJeaLstP/UODVpGsr5OhXhhXg6f+qtJ8uiZ+PUxkDWcgIXLw==
 
-mkdirp@^0.5.1:
-  version "0.5.1"
-  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.1.tgz#30057438eac6cf7f8c4767f38648d6697d75c903"
+mkdirp@0.5.5:
+  version "0.5.5"
+  resolved "https://registry.yarnpkg.com/mkdirp/-/mkdirp-0.5.5.tgz#d91cefd62d1436ca0f41620e251288d420099def"
+  integrity sha512-NKmAlESf6jMGym1++R0Ra7wvhV+wFW63FaSOFPwRahvea0gMUcGUhVeAg/0BC0wiv9ih5NYPB1Wn1UEI1/L+xQ==
   dependencies:
-    minimist "0.0.8"
+    minimist "^1.2.5"
 
 ms@2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.0.0.tgz#5608aeadfc00be6c2901df5f9861788de0d597c8"
 
-nise@^1.3.3:
-  version "1.4.2"
-  resolved "https://registry.yarnpkg.com/nise/-/nise-1.4.2.tgz#a9a3800e3994994af9e452333d549d60f72b8e8c"
+nise@^1.4.5:
+  version "1.5.3"
+  resolved "https://registry.yarnpkg.com/nise/-/nise-1.5.3.tgz#9d2cfe37d44f57317766c6e9408a359c5d3ac1f7"
+  integrity sha512-Ymbac/94xeIrMf59REBPOv0thr+CJVFMhrlAkW/gjCIE58BGQdCj0x7KRCb3yz+Ga2Rz3E9XXSvUyyxqqhjQAQ==
   dependencies:
-    "@sinonjs/formatio" "^2.0.0"
-    just-extend "^1.1.27"
-    lolex "^2.3.2"
+    "@sinonjs/formatio" "^3.2.1"
+    "@sinonjs/text-encoding" "^0.7.1"
+    just-extend "^4.0.2"
+    lolex "^5.0.1"
     path-to-regexp "^1.7.0"
-    text-encoding "^0.6.4"
 
 opentype.js@^0.8.0:
   version "0.8.0"
@@ -148,38 +194,33 @@ pseudomap@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/pseudomap/-/pseudomap-1.0.2.tgz#f052a28da70e618917ef0a8ac34c1ae5a68286b3"
 
-samsam@1.3.0:
-  version "1.3.0"
-  resolved "https://registry.yarnpkg.com/samsam/-/samsam-1.3.0.tgz#8d1d9350e25622da30de3e44ba692b5221ab7c50"
-
-sinon@^6.1.3:
-  version "6.1.3"
-  resolved "https://registry.yarnpkg.com/sinon/-/sinon-6.1.3.tgz#98e7d716b7b11f7f1200e9c997e74f50ae094660"
+sinon@6.3.5:
+  version "6.3.5"
+  resolved "https://registry.yarnpkg.com/sinon/-/sinon-6.3.5.tgz#0f6d6a5b4ebaad1f6e8e019395542d1d02c144a0"
+  integrity sha512-xgoZ2gKjyVRcF08RrIQc+srnSyY1JDJtxu3Nsz07j1ffjgXoY6uPLf/qja6nDBZgzYYEovVkFryw2+KiZz11xQ==
   dependencies:
-    "@sinonjs/formatio" "^2.0.0"
-    "@sinonjs/samsam" "^2.0.0"
+    "@sinonjs/commons" "^1.0.2"
+    "@sinonjs/formatio" "^3.0.0"
+    "@sinonjs/samsam" "^2.1.2"
     diff "^3.5.0"
     lodash.get "^4.4.2"
-    lolex "^2.4.2"
-    nise "^1.3.3"
-    supports-color "^5.4.0"
+    lolex "^2.7.5"
+    nise "^1.4.5"
+    supports-color "^5.5.0"
     type-detect "^4.0.8"
 
-supports-color@^5.4.0:
-  version "5.4.0"
-  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.4.0.tgz#1c6b337402c2137605efe19f10fec390f6faab54"
+supports-color@^5.5.0:
+  version "5.5.0"
+  resolved "https://registry.yarnpkg.com/supports-color/-/supports-color-5.5.0.tgz#e2e69a44ac8772f78a1ec0b35b689df6530efc8f"
+  integrity sha512-QjVjwdXIt408MIiAqCX4oUKsgU2EqAGzs2Ppkm4aQYbjm+ZEWEcW4SfFNTr4uMNZma0ey4f5lgLrkB0aX0QMow==
   dependencies:
     has-flag "^3.0.0"
 
-text-encoding@^0.6.4:
-  version "0.6.4"
-  resolved "https://registry.yarnpkg.com/text-encoding/-/text-encoding-0.6.4.tgz#e399a982257a276dae428bb92845cb71bdc26d19"
-
 tiny-inflate@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/tiny-inflate/-/tiny-inflate-1.0.2.tgz#93d9decffc8805bd57eae4310f0b745e9b6fb3a7"
 
-type-detect@^4.0.8:
+type-detect@4.0.8, type-detect@^4.0.8:
   version "4.0.8"
   resolved "https://registry.yarnpkg.com/type-detect/-/type-detect-4.0.8.tgz#7646fb5f18871cfbb7749e69bd39a6388eb7450c"