diff --git a/.travis.yml b/.travis.yml
index f14bfd03e..27a4d032a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -37,8 +37,7 @@ before_install:
     STRIPE_MOCK_PID=$!
 
 install:
-  - pip install --upgrade pipenv
-  - pipenv install --dev
+  - make init
 
 script:
   - if [[ $TRAVIS_PYTHON_VERSION == '2.7' ]]; then make lint; fi
diff --git a/Makefile b/Makefile
index 0bd069447..ea8ffd119 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,7 @@
+init:
+	pip install pipenv --upgrade
+	pipenv install --dev --skip-lock
+
 test:
 	pipenv run detox
 
diff --git a/Pipfile.lock b/Pipfile.lock
index b2b2f7458..66fc14a8a 100644
--- a/Pipfile.lock
+++ b/Pipfile.lock
@@ -18,10 +18,10 @@
     "default": {
         "certifi": {
             "hashes": [
-                "sha256:13e698f54293db9f89122b0581843a782ad0934a4fe0172d2a980ba77fc61bb7",
-                "sha256:9fa520c1bacfb634fa7af20a76bcbd3d5fb390481724c597da32c719a7dca4b0"
+                "sha256:339dc09518b07e2fa7eda5450740925974815557727d6bd35d319c1524a04a4c",
+                "sha256:6d58c986d22b038c8c0df30d639f23a3e6d172a05c3583e766f4c0b785c0986a"
             ],
-            "version": "==2018.4.16"
+            "version": "==2018.10.15"
         },
         "chardet": {
             "hashes": [
@@ -39,11 +39,10 @@
         },
         "requests": {
             "hashes": [
-                "sha256:63b52e3c866428a224f97cab011de738c36aec0185aa91cfacd418b5d58911d1",
-                "sha256:ec22d826a36ed72a7358ff3fe56cbd4ba69dd7a6718ffd450ff0e9df7a47ce6a"
+                "sha256:99dcfdaaeb17caf6e526f32b6a7b780461512ab3f1d992187801694cba42770c",
+                "sha256:a84b8c9ab6239b578f22d1c21d51b696dcfe004032bb80ea832398d6909d7279"
             ],
-            "markers": "python_version != '3.1.*' and python_version < '4' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.6'",
-            "version": "==2.19.1"
+            "version": "==2.20.0"
         },
         "stripe": {
             "editable": true,
@@ -51,11 +50,10 @@
         },
         "urllib3": {
             "hashes": [
-                "sha256:a68ac5e15e76e7e5dd2b8f94007233e01effe3e50e8daddf69acfd81cb686baf",
-                "sha256:b5725a0bd4ba422ab0e66e89e030c806576753ea3ee08554382c14e685d117b5"
+                "sha256:61bf29cada3fc2fbefad4fdf059ea4bd1b4a86d2b6d15e1c7c0b582b9752fe39",
+                "sha256:de9529817c93f27c8ccbfead6985011db27bd0ddfcdb2d86f3f663385c6a9c22"
             ],
-            "markers": "python_version != '3.1.*' and python_version < '4' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.6'",
-            "version": "==1.23"
+            "version": "==1.24.1"
         }
     },
     "develop": {
@@ -64,29 +62,28 @@
                 "sha256:37228cda29411948b422fae072f57e31d3396d2ee1c9783775980ee9c9990af6",
                 "sha256:58587dd4dc3daefad0487f6d9ae32b4542b185e1c36db6993290e7c41ca2b47c"
             ],
-            "markers": "python_version != '3.1.*' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.7'",
             "version": "==1.5"
         },
         "atomicwrites": {
             "hashes": [
-                "sha256:240831ea22da9ab882b551b31d4225591e5e447a68c5e188db5b89ca1d487585",
-                "sha256:a24da68318b08ac9c9c45029f4a10371ab5b20e4226738e150e6e7c571630ae6"
+                "sha256:0312ad34fcad8fac3704d441f7b317e50af620823353ec657a53e981f92920c0",
+                "sha256:ec9ae8adaae229e4f8446952d204a3e4b5fdd2d099f9be3aaf556120135fb3ee"
             ],
-            "version": "==1.1.5"
+            "version": "==1.2.1"
         },
         "attrs": {
             "hashes": [
-                "sha256:4b90b09eeeb9b88c35bc642cbac057e45a5fd85367b985bd2809c62b7b939265",
-                "sha256:e0d0eb91441a3b53dab4d9b743eafc1ac44476296a2053b6ca3af0b139faf87b"
+                "sha256:10cbf6e27dbce8c30807caf056c8eb50917e0eaafe86347671b57254006c3e69",
+                "sha256:ca4be454458f9dec299268d472aaa5a11f67a4ff70093396e1ceae9c76cf4bbb"
             ],
-            "version": "==18.1.0"
+            "version": "==18.2.0"
         },
         "certifi": {
             "hashes": [
-                "sha256:13e698f54293db9f89122b0581843a782ad0934a4fe0172d2a980ba77fc61bb7",
-                "sha256:9fa520c1bacfb634fa7af20a76bcbd3d5fb390481724c597da32c719a7dca4b0"
+                "sha256:339dc09518b07e2fa7eda5450740925974815557727d6bd35d319c1524a04a4c",
+                "sha256:6d58c986d22b038c8c0df30d639f23a3e6d172a05c3583e766f4c0b785c0986a"
             ],
-            "version": "==2018.4.16"
+            "version": "==2018.10.15"
         },
         "chardet": {
             "hashes": [
@@ -99,6 +96,7 @@
             "hashes": [
                 "sha256:03481e81d558d30d230bc12999e3edffe392d244349a90f4ef9b88425fac74ba",
                 "sha256:0b136648de27201056c1869a6c0d4e23f464750fd9a9ba9750b8336a244429ed",
+                "sha256:0bf8cbbd71adfff0ef1f3a1531e6402d13b7b01ac50a79c97ca15f030dba6306",
                 "sha256:10a46017fef60e16694a30627319f38a2b9b52e90182dddb6e37dcdab0f4bf95",
                 "sha256:198626739a79b09fa0a2f06e083ffd12eb55449b5f8bfdbeed1df4910b2ca640",
                 "sha256:23d341cdd4a0371820eb2b0bd6b88f5003a7438bbedb33688cd33b8eae59affd",
@@ -127,26 +125,33 @@
                 "sha256:c1bb572fab8208c400adaf06a8133ac0712179a334c09224fb11393e920abcdd",
                 "sha256:de4418dadaa1c01d497e539210cb6baa015965526ff5afc078c57ca69160108d",
                 "sha256:e05cb4d9aad6233d67e0541caa7e511fa4047ed7750ec2510d466e806e0255d6",
+                "sha256:f05a636b4564104120111800021a92e43397bc12a5c72fed7036be8556e0029e",
                 "sha256:f3f501f345f24383c0000395b26b726e46758b71393267aeae0bd36f8b3ade80"
             ],
-            "markers": "python_version != '3.1.*' and python_version < '4' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.6'",
             "version": "==4.5.1"
         },
         "coveralls": {
             "hashes": [
-                "sha256:32569a43c9dbc13fa8199247580a4ab182ef439f51f65bb7f8316d377a1340e8",
-                "sha256:664794748d2e5673e347ec476159a9d87f43e0d2d44950e98ed0e27b98da8346"
+                "sha256:ab638e88d38916a6cedbf80a9cd8992d5fa55c77ab755e262e00b36792b7cd6d",
+                "sha256:b2388747e2529fa4c669fb1e3e2756e4e07b6ee56c7d9fce05f35ccccc913aa0"
             ],
             "index": "pypi",
-            "version": "==1.3.0"
+            "version": "==1.5.1"
         },
         "detox": {
             "hashes": [
-                "sha256:cb24895a0e4f95c0bcb1087a201c453600e075568af00848e91518fb2b984568",
-                "sha256:f3119bca4444f1e8a1d7189b064c52cfdd9a89ad3a1c921d78b49bf7f5dc5b1b"
+                "sha256:20dd67705cbde36752b1a522891d93c8444fd2a1500b9a7d08f57ec3a7856efb",
+                "sha256:611022c742ca7dea4b35033b047cc1f7cc5f4a6595f9582aaa4012fa0d8deb32"
             ],
             "index": "pypi",
-            "version": "==0.12"
+            "version": "==0.18"
+        },
+        "dnspython": {
+            "hashes": [
+                "sha256:40f563e1f7a7b80dc5a4e76ad75c23da53d62f1e15e6e517293b04e1f84ead7c",
+                "sha256:861e6e58faa730f9845aaaa9c6c832851fbf89382ac52915a51f89c71accdd31"
+            ],
+            "version": "==1.15.0"
         },
         "docopt": {
             "hashes": [
@@ -156,50 +161,56 @@
         },
         "eventlet": {
             "hashes": [
-                "sha256:06cffa55b335cc4fc32d0079242a81e8a9cddf2581d64d5f0543e2d412b26ca8",
-                "sha256:554a50dad7abee0a9775b0780ce9d9c0bd9123dda4743c46d4314170267c6c47"
+                "sha256:c584163e006e613707e224552fafc63e4e0aa31d7de0ab18b481ac0b385254c8",
+                "sha256:d9d31a3c8dbcedbcce5859a919956d934685b17323fc80e1077cb344a2ffa68d"
             ],
-            "version": "==0.23.0"
+            "version": "==0.24.1"
         },
         "execnet": {
             "hashes": [
                 "sha256:a7a84d5fa07a089186a329528f127c9d73b9de57f1a1131b82bb5320ee651f6a",
                 "sha256:fc155a6b553c66c838d1a22dba1dc9f5f505c43285a878c6f74a79c024750b83"
             ],
-            "markers": "python_version != '3.1.*' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.7'",
             "version": "==1.5.0"
         },
+        "filelock": {
+            "hashes": [
+                "sha256:b8d5ca5ca1c815e1574aee746650ea7301de63d87935b3463d26368b76e31633",
+                "sha256:d610c1bb404daf85976d7a82eb2ada120f04671007266b708606565dd03b5be6"
+            ],
+            "version": "==3.0.10"
+        },
         "flake8": {
             "hashes": [
-                "sha256:7253265f7abd8b313e3892944044a365e3f4ac3fcdcfb4298f55ee9ddf188ba0",
-                "sha256:c7841163e2b576d435799169b78703ad6ac1bbb0f199994fc05f700b2a90ea37"
+                "sha256:6a35f5b8761f45c5513e3405f110a86bea57982c3b75b766ce7b65217abe1670",
+                "sha256:c01f8a3963b3571a8e6bd7a4063359aff90749e160778e03817cd9b71c9e07d2"
             ],
             "index": "pypi",
-            "version": "==3.5.0"
+            "version": "==3.6.0"
         },
         "greenlet": {
             "hashes": [
-                "sha256:0411b5bf0de5ec11060925fd811ad49073fa19f995bcf408839eb619b59bb9f7",
-                "sha256:131f4ed14f0fd28d2a9fa50f79a57d5ed1c8f742d3ccac3d773fee09ef6fe217",
-                "sha256:13510d32f8db72a0b3e1720dbf8cba5c4eecdf07abc4cb631982f51256c453d1",
-                "sha256:31dc4d77ef04ab0460d024786f51466dbbc274fda7c8aad0885a6df5ff8d642e",
-                "sha256:35021d9fecea53b21e4defec0ff3ad69a8e2b75aca1ceddd444a5ba71216547e",
-                "sha256:426a8ef9e3b97c27e841648241c2862442c13c91ec4a48c4a72b262ccf30add9",
-                "sha256:58217698193fb94f3e6ff57eed0ae20381a8d06c2bc10151f76c06bb449a3a19",
-                "sha256:5f45adbbb69281845981bb4e0a4efb8a405f10f3cd6c349cb4a5db3357c6bf93",
-                "sha256:5fdb524767288f7ad161d2182f7ed6cafc0a283363728dcd04b9485f6411547c",
-                "sha256:71fbee1f7ef3fb42efa3761a8faefc796e7e425f528de536cfb4c9de03bde885",
-                "sha256:80bd314157851d06f7db7ca527082dbb0ee97afefb529cdcd59f7a5950927ba0",
-                "sha256:b843c9ef6aed54a2649887f55959da0031595ccfaf7e7a0ba7aa681ffeaa0aa1",
-                "sha256:c6a05ef8125503d2d282ccf1448e3599b8a6bd805c3cdee79760fa3da0ea090e",
-                "sha256:deeda2769a52db840efe5bf7bdf7cefa0ae17b43a844a3259d39fb9465c8b008",
-                "sha256:e66f8b09eec1afdcab947d3a1d65b87b25fde39e9172ae1bec562488335633b4",
-                "sha256:e8db93045414980dbada8908d49dbbc0aa134277da3ff613b3e548cb275bdd37",
-                "sha256:f1cc268a15ade58d9a0c04569fe6613e19b8b0345b64453064e2c3c6d79051af",
-                "sha256:fe3001b6a4f3f3582a865b9e5081cc548b973ec20320f297f5e2d46860e9c703",
-                "sha256:fe85bf7adb26eb47ad53a1bae5d35a28df16b2b93b89042a3a28746617a4738d"
-            ],
-            "version": "==0.4.14"
+                "sha256:000546ad01e6389e98626c1367be58efa613fa82a1be98b0c6fc24b563acc6d0",
+                "sha256:0d48200bc50cbf498716712129eef819b1729339e34c3ae71656964dac907c28",
+                "sha256:23d12eacffa9d0f290c0fe0c4e81ba6d5f3a5b7ac3c30a5eaf0126bf4deda5c8",
+                "sha256:37c9ba82bd82eb6a23c2e5acc03055c0e45697253b2393c9a50cef76a3985304",
+                "sha256:51503524dd6f152ab4ad1fbd168fc6c30b5795e8c70be4410a64940b3abb55c0",
+                "sha256:8041e2de00e745c0e05a502d6e6db310db7faa7c979b3a5877123548a4c0b214",
+                "sha256:81fcd96a275209ef117e9ec91f75c731fa18dcfd9ffaa1c0adbdaa3616a86043",
+                "sha256:853da4f9563d982e4121fed8c92eea1a4594a2299037b3034c3c898cb8e933d6",
+                "sha256:8b4572c334593d449113f9dc8d19b93b7b271bdbe90ba7509eb178923327b625",
+                "sha256:9416443e219356e3c31f1f918a91badf2e37acf297e2fa13d24d1cc2380f8fbc",
+                "sha256:9854f612e1b59ec66804931df5add3b2d5ef0067748ea29dc60f0efdcda9a638",
+                "sha256:99a26afdb82ea83a265137a398f570402aa1f2b5dfb4ac3300c026931817b163",
+                "sha256:a19bf883b3384957e4a4a13e6bd1ae3d85ae87f4beb5957e35b0be287f12f4e4",
+                "sha256:a9f145660588187ff835c55a7d2ddf6abfc570c2651c276d3d4be8a2766db490",
+                "sha256:ac57fcdcfb0b73bb3203b58a14501abb7e5ff9ea5e2edfa06bb03035f0cff248",
+                "sha256:bcb530089ff24f6458a81ac3fa699e8c00194208a724b644ecc68422e1111939",
+                "sha256:beeabe25c3b704f7d56b573f7d2ff88fc99f0138e43480cecdfcaa3b87fe4f87",
+                "sha256:d634a7ea1fc3380ff96f9e44d8d22f38418c1c381d5fac680b272d7d90883720",
+                "sha256:d97b0661e1aead761f0ded3b769044bb00ed5d33e1ec865e891a8b128bf7c656"
+            ],
+            "version": "==0.4.15"
         },
         "idna": {
             "hashes": [
@@ -215,81 +226,70 @@
             ],
             "version": "==0.6.1"
         },
-        "more-itertools": {
+        "monotonic": {
             "hashes": [
-                "sha256:2b6b9893337bfd9166bee6a62c2b0c9fe7735dcf85948b387ec8cba30e85d8e8",
-                "sha256:6703844a52d3588f951883005efcf555e49566a48afd4db4e965d69b883980d3",
-                "sha256:a18d870ef2ffca2b8463c0070ad17b5978056f403fb64e3f15fe62a52db21cc0"
+                "sha256:23953d55076df038541e648a53676fb24980f7a1be290cdda21300b3bc21dfb0",
+                "sha256:552a91f381532e33cbd07c6a2655a21908088962bb8fa7239ecbcc6ad1140cc7"
             ],
-            "version": "==4.2.0"
+            "version": "==1.5"
         },
-        "packaging": {
+        "more-itertools": {
             "hashes": [
-                "sha256:e9215d2d2535d3ae866c3d6efc77d5b24a0192cce0ff20e42896cc0664f889c0",
-                "sha256:f019b770dd64e585a99714f1fd5e01c7a8f11b45635aa953fd41c689a657375b"
+                "sha256:c187a73da93e7a8acc0001572aebc7e3c69daf7bf6881a2cea10650bd4420092",
+                "sha256:c476b5d3a34e12d40130bc2f935028b5f636df8f372dc2c1c01dc19681b2039e",
+                "sha256:fcbfeaea0be121980e15bc97b3817b5202ca73d0eae185b4550cbfce2a3ebb3d"
             ],
-            "version": "==17.1"
+            "version": "==4.3.0"
         },
         "pluggy": {
             "hashes": [
-                "sha256:7f8ae7f5bdf75671a718d2daf0a64b7885f74510bcd98b1a0bb420eb9a9d0cff",
-                "sha256:d345c8fe681115900d6da8d048ba67c25df42973bda370783cd58826442dcd7c",
-                "sha256:e160a7fcf25762bb60efc7e171d4497ff1d8d2d75a3d0df7a21b76821ecbf5c5"
+                "sha256:447ba94990e8014ee25ec853339faf7b0fc8050cdc3289d4d71f7f410fb90095",
+                "sha256:bde19360a8ec4dfd8a20dcb811780a30998101f078fc7ded6162f0076f50508f"
             ],
-            "markers": "python_version != '3.1.*' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.7'",
-            "version": "==0.6.0"
+            "version": "==0.8.0"
         },
         "py": {
             "hashes": [
-                "sha256:3fd59af7435864e1a243790d322d763925431213b6b8529c6ca71081ace3bbf7",
-                "sha256:e31fb2767eb657cbde86c454f02e99cb846d3cd9d61b318525140214fdc0e98e"
+                "sha256:bf92637198836372b520efcba9e020c330123be8ce527e535d185ed4b6f45694",
+                "sha256:e76826342cefe3c3d5f7e8ee4316b80d1dd8a300781612ddbc765c17ba25a6c6"
             ],
-            "markers": "python_version != '3.1.*' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.7'",
-            "version": "==1.5.4"
+            "version": "==1.7.0"
         },
         "pycodestyle": {
             "hashes": [
-                "sha256:682256a5b318149ca0d2a9185d365d8864a768a28db66a84a2ea946bcc426766",
-                "sha256:6c4245ade1edfad79c3446fadfc96b0de2759662dc29d07d80a6f27ad1ca6ba9"
+                "sha256:cbc619d09254895b0d12c2c691e237b2e91e9b2ecf5e84c26b35400f93dcfb83",
+                "sha256:cbfca99bd594a10f674d0cd97a3d802a1fdef635d4361e1a2658de47ed261e3a"
             ],
-            "version": "==2.3.1"
+            "version": "==2.4.0"
         },
         "pyflakes": {
             "hashes": [
-                "sha256:08bd6a50edf8cffa9fa09a463063c425ecaaf10d1eb0335a7e8b1401aef89e6f",
-                "sha256:8d616a382f243dbf19b54743f280b80198be0bca3a5396f1d2e1fca6223e8805"
-            ],
-            "version": "==1.6.0"
-        },
-        "pyparsing": {
-            "hashes": [
-                "sha256:0832bcf47acd283788593e7a0f542407bd9550a55a8a8435214a1960e04bcb04",
-                "sha256:fee43f17a9c4087e7ed1605bd6df994c6173c1e977d7ade7b651292fab2bd010"
+                "sha256:9a7662ec724d0120012f6e29d6248ae3727d821bba522a0e6b356eff19126a49",
+                "sha256:f661252913bc1dbe7fcfcbf0af0db3f42ab65aabd1a6ca68fe5d466bace94dae"
             ],
-            "version": "==2.2.0"
+            "version": "==2.0.0"
         },
         "pytest": {
             "hashes": [
-                "sha256:0453c8676c2bee6feb0434748b068d5510273a916295fd61d306c4f22fbfd752",
-                "sha256:4b208614ae6d98195430ad6bde03641c78553acee7c83cec2e85d613c0cd383d"
+                "sha256:630ff1dbe04f469ee78faa5660f712e58b953da7df22ea5d828c9012e134da43",
+                "sha256:a2b5232735dd0b736cbea9c0f09e5070d78fcaba2823a4f6f09d9a81bd19415c"
             ],
             "index": "pypi",
-            "version": "==3.6.3"
+            "version": "==3.10.0"
         },
         "pytest-cov": {
             "hashes": [
-                "sha256:03aa752cf11db41d281ea1d807d954c4eda35cfa1b21d6971966cc041bbf6e2d",
-                "sha256:890fe5565400902b0c78b5357004aab1c814115894f4f21370e2433256a3eeec"
+                "sha256:513c425e931a0344944f84ea47f3956be0e416d95acbd897a44970c8d926d5d7",
+                "sha256:e360f048b7dae3f2f2a9a4d067b2dd6b6a015d384d1577c994a43f3f7cbad762"
             ],
             "index": "pypi",
-            "version": "==2.5.1"
+            "version": "==2.6.0"
         },
         "pytest-forked": {
             "hashes": [
                 "sha256:e4500cd0509ec4a26535f7d4112a8cc0f17d3a41c29ffd4eab479d2a55b30805",
                 "sha256:f275cb48a73fc61a6710726348e1da6d68a978f0ec0c54ece5a5fae5977e5a08"
             ],
-            "markers": "python_version != '3.1.*' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.7'",
             "version": "==0.2"
         },
         "pytest-mock": {
@@ -302,19 +302,18 @@
         },
         "pytest-xdist": {
             "hashes": [
-                "sha256:48868d1f461122ac8c5fb60487b6da03c0d73dcb06a9d79e06c4eab8ef62a5c3",
-                "sha256:68b084892c1b25998cf6d63cb401f3bed29a7a14be64a55716dc9eb1c9804968"
+                "sha256:3bc9dcb6ff47e607d3c710727cd9996fd7ac1466d405c3b40bb495da99b6b669",
+                "sha256:8e188d13ce6614c7a678179a76f46231199ffdfe6163de031c17e62ffa256917"
             ],
             "index": "pypi",
-            "version": "==1.22.3"
+            "version": "==1.24.0"
         },
         "requests": {
             "hashes": [
-                "sha256:63b52e3c866428a224f97cab011de738c36aec0185aa91cfacd418b5d58911d1",
-                "sha256:ec22d826a36ed72a7358ff3fe56cbd4ba69dd7a6718ffd450ff0e9df7a47ce6a"
+                "sha256:99dcfdaaeb17caf6e526f32b6a7b780461512ab3f1d992187801694cba42770c",
+                "sha256:a84b8c9ab6239b578f22d1c21d51b696dcfe004032bb80ea832398d6909d7279"
             ],
-            "markers": "python_version != '3.1.*' and python_version < '4' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.6'",
-            "version": "==2.19.1"
+            "version": "==2.20.0"
         },
         "six": {
             "hashes": [
@@ -323,29 +322,34 @@
             ],
             "version": "==1.11.0"
         },
+        "toml": {
+            "hashes": [
+                "sha256:229f81c57791a41d65e399fc06bf0848bab550a9dfd5ed66df18ce5f05e73d5c",
+                "sha256:235682dd292d5899d361a811df37e04a8828a5b1da3115886b73cf81ebc9100e"
+            ],
+            "version": "==0.10.0"
+        },
         "tox": {
             "hashes": [
-                "sha256:4df108a1fcc93a7ee4ac97e1a3a1fc3d41ddd22445d518976604e2ef05025280",
-                "sha256:9f0cbcc36e08c2c4ae90d02d3d1f9a62231f974bcbc1df85e8045946d8261059"
+                "sha256:513e32fdf2f9e2d583c2f248f47ba9886428c949f068ac54a0469cac55df5862",
+                "sha256:75fa30e8329b41b664585f5fb837e23ce1d7e6fa1f7811f2be571c990f9d911b"
             ],
             "index": "pypi",
-            "version": "==3.1.2"
+            "version": "==3.5.3"
         },
         "urllib3": {
             "hashes": [
-                "sha256:a68ac5e15e76e7e5dd2b8f94007233e01effe3e50e8daddf69acfd81cb686baf",
-                "sha256:b5725a0bd4ba422ab0e66e89e030c806576753ea3ee08554382c14e685d117b5"
+                "sha256:61bf29cada3fc2fbefad4fdf059ea4bd1b4a86d2b6d15e1c7c0b582b9752fe39",
+                "sha256:de9529817c93f27c8ccbfead6985011db27bd0ddfcdb2d86f3f663385c6a9c22"
             ],
-            "markers": "python_version != '3.1.*' and python_version < '4' and python_version != '3.3.*' and python_version != '3.2.*' and python_version != '3.0.*' and python_version >= '2.6'",
-            "version": "==1.23"
+            "version": "==1.24.1"
         },
         "virtualenv": {
             "hashes": [
-                "sha256:2ce32cd126117ce2c539f0134eb89de91a8413a29baac49cbab3eb50e2026669",
-                "sha256:ca07b4c0b54e14a91af9f34d0919790b016923d157afda5efdde55c96718f752"
+                "sha256:686176c23a538ecc56d27ed9d5217abd34644823d6391cbeb232f42bf722baad",
+                "sha256:f899fafcd92e1150f40c8215328be38ff24b519cd95357fa6e78e006c7638208"
             ],
-            "markers": "python_version != '3.1.*' and python_version != '3.2.*' and python_version >= '2.7' and python_version != '3.0.*'",
-            "version": "==16.0.0"
+            "version": "==16.1.0"
         }
     }
 }
diff --git a/setup.py b/setup.py
index f67092ba0..930c9615d 100644
--- a/setup.py
+++ b/setup.py
@@ -44,8 +44,8 @@ def run_tests(self):
     package_data={'stripe': ['data/ca-certificates.crt']},
     zip_safe=False,
     install_requires=[
-        'requests >= 2; python_version >= "3.0"',
-        'requests[security] >= 2; python_version < "3.0"',
+        'requests >= 2.20; python_version >= "3.0"',
+        'requests[security] >= 2.20; python_version < "3.0"',
     ],
     python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*",
     tests_require=[