Welcome to libpqxx 7.8.0. Lots of goodies for you. Probably enough that I could have called it 8.0 — except libpqxx 8.0 is going to require C++20. For now you're still fine with C++17.

In 7.8 you get, among other things:

• Streaming large data sets now benchmarks faster than similar C/libpq code!
• New array class for easier parsing of SQL arrays.
• Deprecating stream_from. Use transaction_base::stream().
• Use array_parser only on comma-separated types, i.e. most of them. (#590)
• Bumping requirements versions: need postgres 10.
• Fix array_parser bug when parsing semicolon in an unquoted string.
• Make some zview constructors noexcept if string_view does it.
• Handle result status code for starting streaming replication. (#631)
• Faster text decoding and escaping in data streaming. (#601)
• Deprecate basic_fieldstream and fieldstream.
• Deprecate << operator inserting a field into an ostream.
• New string conversion fields: converts_to_string & converts_from_string.
• Support std::optional<std::string_view> etc. in stream_to. (#596)
• Remove support for single-quoted array/composite elements. No such thing!
• Work around build warning in MinGW: include winsock2.h before windows.h.
• If CMake can't find libpq, fall back to pkg-config. (#664)
• Work around spurious compile error on g++ pre-gcc-10. (#665)
• Include <pqxx/range> and <pqxx/time> headers in <pqxx/pqxx>. (#667)
• Don't use std::function as deleter for smart pointers.
• Work around gcc compile error with regex + address sanitizer + analyzers.
• Fix "double free" on exit when built as shared library on Debian. (#681)
• Stop including <ciso646>; should be built into compilers. (#680)
• New broken_connection exception subclass: protocol_violation. (#686)
• Retired unused blob_already_exists exception class. (#686)
• Support for PQinitOpenSSL(). (#678)
• Slightly more helpful error for unsupported conversions. (#695)
• Replace some C++ feature tests with C++20 feature macros.
• Support moving of stream_to. (#706)
• Incorporate source_location in exceptions.

There were some other small tweaks as well. If you implement the text conversions for your own types, there are two new fields that your string_traits specialisation: converts_to_string and converts_from_string. These are booleans that should say whether the string_traits class implements conversion, respectively, from the type to a string; and from a string to the type.

Enjoy this one! I'm sure somebody will find a problem, with so many changes, in which case we'll to a 7.8.1 soon.