diff --git a/src/provider/update.py b/src/provider/update.py
index 8765a0958..6e64fb9d3 100755
--- a/src/provider/update.py
+++ b/src/provider/update.py
@@ -27,50 +27,64 @@ def file2url(f):
 
 def process_data(data, file):
     global out_all, out_domains, count
-    status = data.get("state", "")
+    status = data.get("status", "")
     out_provider = "    static ref P" + str(count) + ": Provider = Provider {\n"
     if status == "OK" or status == "PREPARATION" or status == "BROKEN":
         out_provider += "        status: Status::" + status + ",\n"
     else:
-        print("ERROR: bad state")
-        return
+        raise TypeError("bad status")
 
     comment = ""
     if not "domains" in data:
-        print("ERROR: no domains found")
-        return
+        raise TypeError("no domains found")
     for domain in data["domains"]:
         out_domains += "        (\"" + domain + "\", &*P" + str(count) + "),\n"
         comment += domain + ", "
 
     out_server = ""
+    has_imap = False
+    has_smtp = False
     if "server" in data:
         for s in data["server"]:
             hostname = cleanstr(s.get("hostname", ""))
             port = int(s.get("port", ""))
             if hostname == "" or hostname.count(".") < 1 or port <= 0:
-                print("ERROR: bad hostname or port")
-                return
-            out_server += "            Server {"
-            out_server += " protocol: " + s.get("type", "<bad type>").upper() + ","
-            out_server += " socket: " + s.get("socket", "<bad socket>").upper() + ","
-            out_server += " hostname: \"" + hostname + "\","
-            out_server += " port: " + str(port) + ","
-            out_server += " username_pattern: " + s.get("username_pattern", "EMAIL").upper()
-            out_server += " }\n"
+                raise TypeError("bad hostname or port")
 
-    out_provider += "        before_login_hint: \"" + cleanstr(data.get("before_login_hint", "")) + "\",\n"
-    out_provider += "        after_login_hint: \"" + cleanstr(data.get("after_login_hint", "")) + "\",\n"
-    out_provider += "        overview_page: \"" + file2url(file) + "\",\n"
-    out_provider += "        server: vec![\n" + out_server + "        ],\n"
-    out_provider += "    };\n\n"
+            protocol = s.get("type", "").upper()
+            if protocol == "IMAP":
+                has_imap = True
+            elif protocol == "SMTP":
+                has_smtp = True
+            else:
+                raise TypeError("bad protocol")
 
-    out_all += "    // " + comment.strip(", ") + "\n" + out_provider
+            socket = s.get("socket", "").upper()
+            if socket != "STARTTLS" and socket != "SSL":
+                raise TypeError("bad socket")
+
+            username_pattern = s.get("username_pattern", "EMAIL").upper()
+            if username_pattern != "EMAIL" and username_pattern != "EMAILLOCALPART":
+                raise TypeError("bad username pattern")
+
+            out_server += ("            Server { protocol: " + protocol + ", socket: " + socket + ", hostname: \""
+            + hostname + "\", port: " + str(port) + ", username_pattern: " + username_pattern + " },\n")
+
+    if (not has_imap and not has_smtp) or (has_imap and has_smtp):
+        out_provider += "        before_login_hint: \"" + cleanstr(data.get("before_login_hint", "")) + "\",\n"
+        out_provider += "        after_login_hint: \"" + cleanstr(data.get("after_login_hint", "")) + "\",\n"
+        out_provider += "        overview_page: \"" + file2url(file) + "\",\n"
+        out_provider += "        server: vec![\n" + out_server + "        ],\n"
+        out_provider += "    };\n\n"
+    else:
+        raise TypeError("SMTP and IMAP must be specified together or left out both")
+
+    out_all += "    // " + file[file.rindex("/")+1:] + ": " + comment.strip(", ") + "\n" + out_provider
 
 
 def process_file(file):
     global count
-    print("processing file: " + file)
+    print("processing file: " + file, file=sys.stderr)
     with open(file) as f:
         # load_all() loads "---"-separated yamls -
         # by coincidence, this is also the frontmatter separator :)
@@ -80,15 +94,16 @@ def process_file(file):
 
 
 def process_dir(dir):
-    print("processing directory: " + dir)
+    print("processing directory: " + dir, file=sys.stderr)
     files = [f for f in os.listdir(dir) if f.endswith(".md")]
+    files.sort()
     for f in files:
         process_file(os.path.join(dir, f))
 
 
 if __name__ == "__main__":
     if len(sys.argv) < 2:
-        raise SystemExit("need argument: path to dir with md/yaml files")
+        raise SystemExit("usage: update.py DIR_WITH_MD_FILES > data.rs")
 
     out_all = ("// file generated by src/provider/update.py\n\n"
     "use crate::provider::*;\n"