Release v4.1.1: Hotfix for ESP8266 and Raspberry Pi Pico

This is a hotfix release that addresses critical compilation errors encountered on ESP8266 and Raspberry Pi Pico platforms, particularly when sending attachments.
A huge thank you to the community members (#54 @JChristensen) who reported these issues!

Bug Fixes

• Fixed encode64 Macro Conflict: A macro named encode64 was causing compilation to fail when sending attachments on ESP8266 and Pico. This has been resolved by renaming the conflicting macro, allowing the Base64 encoding function to be called correctly.
• Corrected client.write Usage: Fixed an "invalid conversion" error by updating the client.write() calls to be compatible with the networking APIs on the affected platforms. This ensures that email content and attachments are sent correctly without compilation failures.

These changes restore full functionality for projects on ESP8266 and Raspberry Pi Pico. Please update to this version if you have experienced these compilation errors.

EMailSender Library v4.1.0

Release Date: November 10, 2025

We are excited to announce the release of EMailSender v4.1.0! This update focuses on enhancing attachment handling, making the library more versatile and memory-efficient, especially for projects on memory-constrained devices.

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✨ What's New in v4.1.0

This version introduces a significant new feature for handling email attachments and provides important stability improvements.

• New Attachment Types: Stream and File Objects
  You can now use Stream and File objects directly as attachments. This is a major improvement that allows you to send large files or dynamic data without loading the entire content into memory first. This is particularly useful for:

  • Sending log files from an SD card or LittleFS.
  • Streaming data directly from sensors or other network sources as an attachment.
  • Reducing the RAM footprint of your application when dealing with attachments.

• Bug Fixes for Attachment Handling
  This release also addresses bugs related to the calculation of attachment size and the Base64 encoding process. These fixes improve the reliability of sending attachments and ensure they are correctly formatted according to SMTP standards.

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As seen in the README.md changelog:

Thanks Renzo

EMailSender Library v4.0.1

Fix sslclient path
Add wrapper for Platformio code completition

EMailSender Library v4.0.0

📝 Changelog v4.0.0 - 08/10/2025

New Features

• ✨ STARTTLS support (Port 587) - Full implementation for secure email on port 587
• ✨ Internal SSLClient integration - Built-in SSL/TLS support for ESP32/ESP8266
• ✨ Enhanced authentication - Better support for various SMTP auth methods
• ✨ Improved error handling - More detailed error messages and responses

Improvements

• 🔧 Unified client handling for better compatibility
• 🔧 Better SSL/TLS handshake management
• 🔧 Improved EHLO/HELO command handling with multi-line response support
• 🔧 Enhanced connection retry logic
• 🔧 Better memory management for large attachments

Bug Fixes

• 🐛 Fixed SSLClient initialization on ESP32
• 🐛 Fixed STARTTLS upgrade sequence
• 🐛 Corrected client scope issues
• 🐛 Fixed BearSSL integration for Ethernet shields

Breaking Changes

• ⚠️ Minimum Arduino IDE version: 1.8.x
• ⚠️ ESP32 core minimum version: 2.0.x (for WiFiClientSecure improvements)
• ⚠️ Some internal API changes (user-facing API remains compatible)

Migration from v3.x

Most code will work without changes. If using custom client configuration:

• Check EMailSenderKey.h for new defines
• Update authentication methods if using advanced features
• Test STARTTLS connections (port 587) for better security

Support for Arudino GIGA WiFi

Added support of Arduino GIGA WiFi.
Section MBED microcontrollers.

`
// Arduino MBED microcontrollers configuration LIKE Arduino GIGA
#ifndef DEFAULT_EMAIL_NETWORK_TYPE_ARDUINO_MBED
#define DEFAULT_EMAIL_NETWORK_TYPE_MBED NETWORK_MBED_WIFI
#define DEFAULT_INTERNAL_ARDUINO_MBED_STORAGE STORAGE_NONE
#define DEFAULT_EXTERNAL_ARDUINO_MBED_STORAGE STORAGE_SD
#endif

`

Fix previous version erros

In the pull request of the previous version, there was an error, we are going to fix It.
Thanks for this forum topic https://mischianti.org/forums/topic/emailsender-not-compiling/ by Mark

Fix warnings

Fixed warning caused by the reuse of a constant.
#43 Thanks to @Patriboom @Andy2015

Add support for Ethernet_Generic and ESP8266SdFat library on Raspberry Pi Pico

Add support for Ethernet_Generic
Add the management of ESP8266SdFat library on Raspberry Pi Pico #forum

Add STM32, Raspberry pi Pico support and some fix

Fix external storage error 404 (#forum
Fix distribution list examples
Add Raspberry Pi Pico W and rp2040 boards
Add STM32 management for https://github.com/rogerclarkmelbourne/Arduino_STM32 library.

Add possibility to disable SSL via define

Add FORCE_DISABLE_SSL to disable SSL if present