diff --git a/client.cpp b/client.cpp
index b4b0c1f..f231e09 100644
--- a/client.cpp
+++ b/client.cpp
@@ -43,9 +43,15 @@ MastodonClient::MastodonClient() {
     try {
         setopt(this->_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_DNS);
         setopt(this->_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_SSL_SESSION);
+#if CURL_AT_LEAST_VERSION(7, 57, 0)
         setopt(this->_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_CONNECT);
+#endif
+#if CURL_AT_LEAST_VERSION(7, 61, 0)
         setopt(this->_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_PSL);
+#endif
+#if CURL_AT_LEAST_VERSION(7, 88, 0)
         setopt(this->_share, CURLSHOPT_SHARE, CURL_LOCK_DATA_HSTS);
+#endif
 
         setopt(this->_share, CURLSHOPT_LOCKFUNC, share_lock);
         setopt(this->_share, CURLSHOPT_UNLOCKFUNC, share_unlock);
@@ -206,7 +212,11 @@ CURL* MastodonClient::_get_easy() {
 
         try {
             setopt(curl, CURLOPT_TIMEOUT_MS, 10000L);
+#if CURL_AT_LEAST_VERSION(7, 85, 0)
             setopt(curl, CURLOPT_PROTOCOLS_STR, "https");
+#else
+            setopt(curl, CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
+#endif
             setopt(curl, CURLOPT_USERAGENT, "Coyote (https://gitlab.com/blankX/coyote; blankie@nixnetmail.com)");
             setopt(curl, CURLOPT_SHARE, this->_share);
         } catch (const std::exception& e) {
@@ -266,7 +276,7 @@ long MastodonClient::_response_status_code() {
 static void lowercase(std::string& str) {
     for (size_t i = 0; i < str.size(); i++) {
         if (str[i] >= 'A' && str[i] <= 'Z') {
-            str[i] = str[i] - static_cast<char>('A' + 'a');
+            str[i] = static_cast<char>(str[i] - 'A' + 'a');
         }
     }
 }
diff --git a/lxb_wrapper.h b/lxb_wrapper.h
index 5008f86..b2ccc01 100644
--- a/lxb_wrapper.h
+++ b/lxb_wrapper.h
@@ -89,6 +89,6 @@ private:
     lxb_html_document_t* _document;
 };
 
-}; // namespace HTML
+} // namespace HTML
 
-}; // namespace LXB
+} // namespace LXB
diff --git a/models.h b/models.h
index ca1f4e0..8c8a4d0 100644
--- a/models.h
+++ b/models.h
@@ -41,7 +41,7 @@ struct Account {
     std::vector<Emoji> emojis;
     std::vector<AccountField> fields;
 
-    constexpr std::string acct(bool always_show_domain = true) const {
+    inline std::string acct(bool always_show_domain = true) const {
         std::string res = this->username;
         if (always_show_domain || !this->same_server) {
             res += '@';
diff --git a/servehelper.cpp b/servehelper.cpp
index 4f0cf91..ffe7104 100644
--- a/servehelper.cpp
+++ b/servehelper.cpp
@@ -29,13 +29,26 @@ static inline Element serialize_poll(const httplib::Request& req, const Poll& po
 
 class CurlUrlException : public std::exception {
 public:
-    CurlUrlException(CURLUcode code_) : code(code_) {}
+    CurlUrlException(CURLUcode code_) : code(code_) {
+#if !CURL_AT_LEAST_VERSION(7, 80, 0)
+        snprintf(this->_id_buf, 64, "curl url error %d", this->code);
+#endif
+    }
 
     const char* what() const noexcept {
+#if CURL_AT_LEAST_VERSION(7, 80, 0)
         return curl_url_strerror(this->code);
+#else
+        return this->_id_buf;
+#endif
     }
 
     CURLUcode code;
+
+private:
+#if !CURL_AT_LEAST_VERSION(7, 80, 0)
+    char _id_buf[64];
+#endif
 };