Update links, README, contributing, etc.

.github/FUNDING.yml

 github: [thinkyhead]
 patreon: thinkyhead
-custom: ["http://www.thinkyhead.com/donate-to-marlin"]
+custom: ["https://www.thinkyhead.com/donate-to-marlin"]

.github/contributing.md

 
 We have a Message Board and a Facebook group where our knowledgable user community can provide helpful advice if you have questions.
 
-* [Marlin RepRap forum](http://forums.reprap.org/list.php?415)
+* [Marlin RepRap forum](https://reprap.org/forum/list.php?415)
 * [MarlinFirmware on Facebook](https://www.facebook.com/groups/1049718498464482/)
 
-If chat is more your speed, you can join the MarlinFirmware Slack team:
+If chat is more your speed, you can join the MarlinFirmware Discord server:
 
-* Join the Marlin Slack Team
-  * To obtain group access, please [send a request](http://www.thinkyhead.com/contact/9) to @thinkyhead.
-  * Even though Slack is a chat service, sometimes it takes several hours for community members to respond — please be patient!
-  * Use the `#general` channel for general questions or discussion about Marlin.
-  * Other channels exist for certain topics. Check the channel list.
+* Use the link https://discord.gg/n5NJ59y to join up as a General User.
+* Even though our Discord is pretty active, it may take a while for community members to respond — please be patient!
+* Use the `#general` channel for general questions or discussion about Marlin.
+* Other channels exist for certain topics or are limited to Patrons. Check the channel list.
 
 ## How Can I Contribute?
 

Marlin/Configuration.h

 //===========================================================================
 //============================= PID Settings ================================
 //===========================================================================
-// PID Tuning Guide here: http://reprap.org/wiki/PID_Tuning
+// PID Tuning Guide here: https://reprap.org/wiki/PID_Tuning
 
 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP

Marlin/Marlin.ino

 
 Getting Help
 
-  - http://forums.reprap.org/list.php?415
+  - https://reprap.org/forum/list.php?415
     The Marlin Discussion Forum is a great place to get help from other Marlin
     users who may have experienced similar issues to your own.
 

Marlin/src/HAL/AVR/fastio.h

  *
  * Now you can simply SET_OUTPUT(PIN); WRITE(PIN, HIGH); WRITE(PIN, LOW);
  *
- * Why double up on these macros? see http://gcc.gnu.org/onlinedocs/cpp/Stringification.html
+ * Why double up on these macros? see https://gcc.gnu.org/onlinedocs/cpp/Stringification.html
  */
 
 #define _READ(IO)             TEST(DIO ## IO ## _RPORT, DIO ## IO ## _PIN)

Marlin/src/HAL/DUE/Tone.cpp

 
 /**
  * Description: Tone function for Arduino Due and compatible (SAM3X8E)
- * Derived from http://forum.arduino.cc/index.php?topic=136500.msg2903012#msg2903012
+ * Derived from https://forum.arduino.cc/index.php?topic=136500.msg2903012#msg2903012
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/fastio.h

  *
  * Now you can simply SET_OUTPUT(STEP); WRITE(STEP, HIGH); WRITE(STEP, LOW);
  *
- * Why double up on these macros? see http://gcc.gnu.org/onlinedocs/cpp/Stringification.html
+ * Why double up on these macros? see https://gcc.gnu.org/onlinedocs/cpp/Stringification.html
  */
 
 // Read a pin

Marlin/src/HAL/DUE/usb/arduino_due_x.h

 #pragma once
 
 /**
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 /**

Marlin/src/HAL/DUE/usb/compiler.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef UTILS_COMPILER_H

Marlin/src/HAL/DUE/usb/conf_access.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _CONF_ACCESS_H_

Marlin/src/HAL/DUE/usb/conf_clock.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef CONF_CLOCK_H_INCLUDED

Marlin/src/HAL/DUE/usb/conf_usb.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _CONF_USB_H_

Marlin/src/HAL/DUE/usb/ctrl_access.c

  *
  ******************************************************************************/
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/ctrl_access.h

  *
  ******************************************************************************/
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 

Marlin/src/HAL/DUE/usb/genclk.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef CHIP_GENCLK_H_INCLUDED

Marlin/src/HAL/DUE/usb/mrepeat.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _MREPEAT_H_

Marlin/src/HAL/DUE/usb/osc.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef CHIP_OSC_H_INCLUDED

Marlin/src/HAL/DUE/usb/pll.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef CHIP_PLL_H_INCLUDED

Marlin/src/HAL/DUE/usb/preprocessor.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _PREPROCESSOR_H_

Marlin/src/HAL/DUE/usb/sbc_protocol.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 #ifndef _SBC_PROTOCOL_H_
 #define _SBC_PROTOCOL_H_

Marlin/src/HAL/DUE/usb/sd_mmc_spi_mem.h

  *
  ******************************************************************************/
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 

Marlin/src/HAL/DUE/usb/spc_protocol.h

  */
 
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 #ifndef _SPC_PROTOCOL_H_
 #define _SPC_PROTOCOL_H_

Marlin/src/HAL/DUE/usb/stringz.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _STRINGZ_H_

Marlin/src/HAL/DUE/usb/sysclk.c

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/sysclk.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef CHIP_SYSCLK_H_INCLUDED

Marlin/src/HAL/DUE/usb/tpaste.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _TPASTE_H_

Marlin/src/HAL/DUE/usb/udc.c

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/udc.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _UDC_H_

Marlin/src/HAL/DUE/usb/udc_desc.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _UDC_DESC_H_

Marlin/src/HAL/DUE/usb/udd.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _UDD_H_

Marlin/src/HAL/DUE/usb/udi.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _UDI_H_

Marlin/src/HAL/DUE/usb/udi_cdc.c

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/udi_cdc.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _UDI_CDC_H_
  * another "Composite Device" module, like "USB HID Mouse (Composite Device)".
  *
  * Also, you can refer to application note
- * <A href="http://www.atmel.com/dyn/resources/prod_documents/doc8445.pdf">
+ * <A href="https://www.atmel.com/dyn/resources/prod_documents/doc8445.pdf">
  * AVR4902 ASF - USB Composite Device</A>.
  *
  * \section udi_cdc_use_case_composite_setup Setup steps

Marlin/src/HAL/DUE/usb/udi_cdc_conf.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _UDI_CDC_CONF_H_

Marlin/src/HAL/DUE/usb/udi_cdc_desc.c

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/udi_composite_desc.c

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/udi_msc.c

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/udi_msc.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _UDI_MSC_H_
  * another "Composite Device" module, like "USB HID Mouse (Composite Device)".
  *
  * Also, you can refer to application note
- * <A href="http://www.atmel.com/dyn/resources/prod_documents/doc8445.pdf">
+ * <A href="https://www.atmel.com/dyn/resources/prod_documents/doc8445.pdf">
  * AVR4902 ASF - USB Composite Device</A>.
  *
  * \section udi_msc_use_case_composite_setup Setup steps

Marlin/src/HAL/DUE/usb/uotghs_device_due.c

  */
 
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifdef ARDUINO_ARCH_SAM

Marlin/src/HAL/DUE/usb/uotghs_device_due.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef UOTGHS_DEVICE_DUE_H_INCLUDED

Marlin/src/HAL/DUE/usb/uotghs_otg.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef UOTGHS_OTG_H_INCLUDED

Marlin/src/HAL/DUE/usb/usb_protocol.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _USB_PROTOCOL_H_

Marlin/src/HAL/DUE/usb/usb_protocol_cdc.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 #ifndef _USB_PROTOCOL_CDC_H_
 #define _USB_PROTOCOL_CDC_H_

Marlin/src/HAL/DUE/usb/usb_protocol_msc.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _USB_PROTOCOL_MSC_H_

Marlin/src/HAL/DUE/usb/usb_task.c

  *
  */
 
-// Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+// Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
 
 #ifdef ARDUINO_ARCH_SAM
 

Marlin/src/HAL/DUE/usb/usb_task.h

  *
  */
 /*
- * Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
+ * Support and FAQ: visit <a href="https://www.atmel.com/design-support/">Atmel Support</a>
  */
 
 #ifndef _USB_TASK_H_

Marlin/src/HAL/LINUX/fastio.h

  *
  * Now you can simply SET_OUTPUT(STEP); WRITE(STEP, HIGH); WRITE(STEP, LOW);
  *
- * Why double up on these macros? see http://gcc.gnu.org/onlinedocs/cpp/Stringification.html
+ * Why double up on these macros? see https://gcc.gnu.org/onlinedocs/gcc-4.8.5/cpp/Stringification.html
  */
 
 /// Read a pin

Marlin/src/HAL/LPC1768/fastio.h

  *
  * Now you can simply SET_OUTPUT(STEP); WRITE(STEP, HIGH); WRITE(STEP, LOW);
  *
- * Why double up on these macros? see http://gcc.gnu.org/onlinedocs/cpp/Stringification.html
+ * Why double up on these macros? see https://gcc.gnu.org/onlinedocs/gcc-4.8.5/cpp/Stringification.html
  */
 
 /// Read a pin

Marlin/src/HAL/STM32F1/SPI.cpp

   /**
    * Notes:
    * As far as we know the AVR numbers for dataMode match the numbers required by the STM32.
-   * From the AVR doc http://www.atmel.com/images/doc2585.pdf section 2.4
+   * From the AVR doc https://www.atmel.com/images/doc2585.pdf section 2.4
    *
    * SPI Mode  CPOL  CPHA  Shift SCK-edge  Capture SCK-edge
    * 0       0     0     Falling     Rising

Marlin/src/HAL/TEENSY31_32/fastio.h

  *
  * Now you can simply SET_OUTPUT(PIN); WRITE(PIN, HIGH); WRITE(PIN, LOW);
  *
- * Why double up on these macros? see http://gcc.gnu.org/onlinedocs/cpp/Stringification.html
+ * Why double up on these macros? see https://gcc.gnu.org/onlinedocs/gcc-4.8.5/cpp/Stringification.html
  */
 
 #define _READ(P) bool(CORE_PIN ## P ## _PINREG & CORE_PIN ## P ## _BITMASK)

Marlin/src/HAL/TEENSY35_36/fastio.h

  *
  * Now you can simply SET_OUTPUT(PIN); WRITE(PIN, HIGH); WRITE(PIN, LOW);
  *
- * Why double up on these macros? see http://gcc.gnu.org/onlinedocs/cpp/Stringification.html
+ * Why double up on these macros? see https://gcc.gnu.org/onlinedocs/gcc-4.8.5/cpp/Stringification.html
  */
 
 #define _READ(P) bool(CORE_PIN ## P ## _PINREG & CORE_PIN ## P ## _BITMASK)

Marlin/src/HAL/shared/backtrace/unwarmbytab.cpp

  *
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  *
  * This library was modified, some bugs fixed, stack address validated
  * and adapted to be used in Marlin 3D printer firmware as backtracer

Marlin/src/feature/dac/dac_mcp4728.cpp

  * mcp4728.cpp - Arduino library for MicroChip MCP4728 I2C D/A converter
  *
  * For implementation details, please take a look at the datasheet:
- * http://ww1.microchip.com/downloads/en/DeviceDoc/22187a.pdf
+ * https://ww1.microchip.com/downloads/en/DeviceDoc/22187a.pdf
  *
  * For discussion and feedback, please go to:
  * http://arduino.cc/forum/index.php/topic,51842.0.html

Marlin/src/gcode/motion/G5.cpp

 
 /**
  * Parameters interpreted according to:
- * http://linuxcnc.org/docs/2.6/html/gcode/parser.html#sec:G5-Cubic-Spline
+ * https://linuxcnc.org/docs/2.6/html/gcode/gcode.html#sec:G5-Cubic-Spline
  * However I, J omission is not supported at this point; all
  * parameters can be omitted and default to zero.
  */

Marlin/src/lcd/extui/lib/ftdi_eve_touch_ui/ftdi_eve_lib/basic/boards.h

 /*
  * Settings for the 4D Systems,        4.3" Embedded SPI Display             480x272, SPI, FT800 (4DLCD-FT843)
  *
- *    http://www.4dsystems.com.au/product/4DLCD_FT843/
+ *    https://4dsystems.com.au/4dlcd-ft843
  *
  * Datasheet:
  *
- *    http://www.4dsystems.com.au/productpages/4DLCD-FT843/downloads/FT843-4.3-Display_datasheet_R_1_2.pdf
+ *    https://4dsystems.com.au/mwdownloads/download/link/id/52/
  *
  */
 
  *
  * Datasheet:
  *
- *    http://www.hantronix.com/files/data/s1501799605s500-gh7.pdf
+ *    https://www.hantronix.com/files/data/s1501799605s500-gh7.pdf
  *
  */
 #elif defined(LCD_ALEPHOBJECTS_CLCD_UI)

Marlin/src/module/scara.cpp

     /**
      * Morgan SCARA Inverse Kinematics. Results in 'delta'.
      *
-     * See http://forums.reprap.org/read.php?185,283327
+     * See https://reprap.org/forum/read.php?185,283327
      *
      * Maths and first version by QHARLEY.
      * Integrated into Marlin and slightly restructured by Joachim Cerny.

Marlin/src/module/thermistor/thermistor_2.h

 
 //
 // R25 = 200 kOhm, beta25 = 4338 K, 4.7 kOhm pull-up, ATC Semitec 204GT-2
-// Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
+// Verified by linagee. Source: https://www.mouser.com/datasheet/2/362/semitec%20usa%20corporation_gtthermistor-1202937.pdf
 // Calculated using 4.7kohm pullup, voltage divider math, and manufacturer provided temp/resistance
 //
 const short temptable_2[][2] PROGMEM = {

Marlin/src/module/thermistor/thermistor_5.h

 // R25 = 100 kOhm, beta25 = 4267 K, 4.7 kOhm pull-up
 // 100k ParCan thermistor (104GT-2)
 // ATC Semitec 104GT-2/104NT-4-R025H42G (Used in ParCan)
-// Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
+// Verified by linagee. Source: https://www.mouser.com/datasheet/2/362/semitec%20usa%20corporation_gtthermistor-1202937.pdf
 // Calculated using 4.7kohm pullup, voltage divider math, and manufacturer provided temp/resistance
 const short temptable_5[][2] PROGMEM = {
   { OV(   1), 713 },

Marlin/src/module/thermistor/thermistor_52.h

 
 // R25 = 200 kOhm, beta25 = 4338 K, 1 kOhm pull-up,
 // 200k ATC Semitec 204GT-2 (WITH 1kohm RESISTOR FOR PULLUP, R9 ON SANGUINOLOLU! NOT FOR 4.7kohm PULLUP! THIS IS NOT NORMAL!)
-// Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
+// Verified by linagee. Source: https://www.mouser.com/datasheet/2/362/semitec%20usa%20corporation_gtthermistor-1202937.pdf
 // Calculated using 1kohm pullup, voltage divider math, and manufacturer provided temp/resistance
 // Advantage: More resolution and better linearity from 150C to 200C
 const short temptable_52[][2] PROGMEM = {

Marlin/src/module/thermistor/thermistor_55.h

 
 // R25 = 100 kOhm, beta25 = 4267 K, 1 kOhm pull-up,
 // 100k ATC Semitec 104GT-2 (Used on ParCan) (WITH 1kohm RESISTOR FOR PULLUP, R9 ON SANGUINOLOLU! NOT FOR 4.7kohm PULLUP! THIS IS NOT NORMAL!)
-// Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
+// Verified by linagee. Source: https://www.mouser.com/datasheet/2/362/semitec%20usa%20corporation_gtthermistor-1202937.pdf
 // Calculated using 1kohm pullup, voltage divider math, and manufacturer provided temp/resistance
 // Advantage: More resolution and better linearity from 150C to 200C
 const short temptable_55[][2] PROGMEM = {

Marlin/src/pins/sam/pins_ALLIGATOR_R2.h

 
 /**
  * Alligator Board R2
- * http://www.3dartists.org/
+ * https://reprap.org/wiki/Alligator_Board
  */
 
 #ifndef __SAM3X8E__

Marlin/src/pins/sanguino/pins_OMCA.h

  *       PWM (D 14) PD6 20|        |21  PD7 (D 15) PWM
  *                        +--------+
  *
- * REF http://sanguino.cc/hardware
+ * REF http://sanguino.wikidot.com/hardware
  */
 
 /**
  *
  * When installing select 1.0.2
  *
- * Installation instructions can be found at https://learn.sparkfun.com/pages/CustomBoardsArduino
+ * Installation instructions can be found at http://learn.sparkfun.com/pages/CustomBoardsArduino
  * Just use the above JSON URL instead of Sparkfun's JSON.
  *
  * Once installed select the Sanguino board and then select the CPU.

Marlin/src/pins/stm32f4/pins_BLACK_STM32F407VE.h

 
 /**
  * STM32F407VET6 with RAMPS-like shield
- * 'Black' STM32F407VET6 board - http://wiki.stm32duino.com/index.php?title=STM32F407
+ * 'Black' STM32F407VET6 board - https://www.stm32duino.com/viewtopic.php?t=485
  * Shield - https://github.com/jmz52/Hardware
  */
 

Marlin/src/sd/SdFatStructs.h

 
 /**
  * mostly from Microsoft document fatgen103.doc
- * http://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx
+ * https://www.microsoft.com/whdc/system/platform/firmware/fatgen.mspx
  */
 
 uint8_t const BOOTSIG0 = 0x55,          // Value for byte 510 of boot block or MBR

Marlin/src/sd/SdInfo.h

 // Version 3.01
 // May 18, 2010
 //
-// http://www.sdcard.org/developers/tech/sdcard/pls/simplified_specs
+// https://www.sdcard.org/downloads/pls/index.html
 
 // SD card commands
 uint8_t const CMD0 = 0x00,    // GO_IDLE_STATE - init card in spi mode if CS low

README.md

  - Chris Pepper [[@p3p](https://github.com/p3p)] - UK
  - Bob Kuhn [[@Bob-the-Kuhn](https://github.com/Bob-the-Kuhn)] - USA
  - João Brazio [[@jbrazio](https://github.com/jbrazio)] - Portugal
- - Erik van der Zalm [[@ErikZalm](https://github.com/ErikZalm)] - Netherlands   [![Flattr Erik](http://api.flattr.com/button/flattr-badge-large.png)](https://flattr.com/submit/auto?user_id=ErikZalm&url=https://github.com/MarlinFirmware/Marlin&title=Marlin&language=&tags=github&category=software)
+ - Erik van der Zalm [[@ErikZalm](https://github.com/ErikZalm)] - Netherlands   [![Flattr Erik](https://api.flattr.com/button/flattr-badge-large.png)](https://flattr.com/submit/auto?user_id=ErikZalm&url=https://github.com/MarlinFirmware/Marlin&title=Marlin&language=&tags=github&category=software)
 
 ## License
 

buildroot/etc/udev/rules.d/99-platformio-udev.rules

 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
-#    http://www.apache.org/licenses/LICENSE-2.0
+#    https://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 #
 # INSTALLATION
 #
-# Please visit > http://docs.platformio.org/en/latest/faq.html#platformio-udev-rules
+# Please visit > https://docs.platformio.org/en/latest/faq.html#platformio-udev-rules
 #
 #####################################################################################
 

buildroot/share/PlatformIO/boards/BigTree_Btt002.json

     "use_1200bps_touch": false,
     "wait_for_upload_port": false
   },
-  "url": "http://www.st.com/en/microcontrollers/stm32f407ve.html",
+  "url": "https://www.st.com/en/microcontrollers-microprocessors/stm32f407vg.html",
   "vendor": "Generic"
 }

buildroot/share/PlatformIO/boards/BigTree_SKR_Pro.json

     "use_1200bps_touch": false,
     "wait_for_upload_port": false
   },
-  "url": "http://www.st.com/en/microcontrollers/stm32f407zg.html",
+  "url": "https://www.st.com/en/microcontrollers-microprocessors/stm32f407zg.html",
   "vendor": "Generic"
 }

buildroot/share/PlatformIO/boards/FLYF407ZG.json

     "use_1200bps_touch": false,
     "wait_for_upload_port": false
   },
-  "url": "http://www.st.com/en/microcontrollers/stm32f407ZG.html",
+  "url": "https://www.st.com/en/microcontrollers-microprocessors/stm32f407ZG.html",
   "vendor": "Generic"
 }

buildroot/share/PlatformIO/boards/blackSTM32F407VET6.json

     "use_1200bps_touch": false,
     "wait_for_upload_port": false
   },
-  "url": "http://www.st.com/en/microcontrollers/stm32f407ve.html",
+  "url": "https://www.st.com/en/microcontrollers-microprocessors/stm32f407ve.html",
   "vendor": "Generic"
 }

buildroot/share/PlatformIO/boards/malyanM200.json

     "use_1200bps_touch": false,
     "wait_for_upload_port": false
   },
-  "url": "http://www.st.com/content/st_com/en/products/microcontrollers/stm32-32-bit-arm-cortex-mcus/stm32f1-series/stm32f103/stm32f103cb.html",
+  "url": "https://www.st.com/content/st_com/en/products/microcontrollers/stm32-32-bit-arm-cortex-mcus/stm32f1-series/stm32f103/stm32f103cb.html",
   "vendor": "Generic"
 }

buildroot/share/fonts/README.md

 The original author of the following font files is [A. Hardtung](https://github.com/AnHardt).
 
 Any copyright is dedicated to the Public Domain.
-http://creativecommons.org/publicdomain/zero/1.0/
+https://creativecommons.org/publicdomain/zero/1.0/
 
  - HD44780_C.fon ([fe2bd23](https://github.com/MarlinFirmware/Marlin/commit/fe2bd237d556439499dfdee852c1550c7a16430a))
  - HD44780_J.fon ([fe2bd23](https://github.com/MarlinFirmware/Marlin/commit/fe2bd237d556439499dfdee852c1550c7a16430a))
 
 
 ## Documentation
-For detailed information about [adding new fonts](http://www.marlinfw.org/docs/development/fonts.html) to Marlin visit our documentation website.
+For detailed information about [adding new fonts](https://www.marlinfw.org/docs/development/fonts.html) to Marlin visit our documentation website.

buildroot/share/fonts/uxggenpages.md

 
 - [WQY](http://wenq.org/)
 - [WQY 9pt bitmap font](http://wenq.org/daily/wqy-bitmapfont-bdf-gb18030-nightly_build.tar.gz)
-- [unifont (16x8 or 16x16)](http://unifoundry.com/unifont.html)
+- [unifont (16x8 or 16x16)](https://unifoundry.com/unifont.html)
 
 Documents related to the old version of the language engine:
 
-- [Marlin Fonts Documentation](http://www.marlinfw.org/docs/development/fonts.html)
-- [Marlin LCD Language](http://marlinfw.org/docs/development/lcd_language.html)
+- [Marlin Fonts Documentation](https://www.marlinfw.org/docs/development/fonts.html)
+- [Marlin LCD Language](https://marlinfw.org/docs/development/lcd_language.html)
 - [U8GLIB](https://github.com/olikraus/u8glib.git)
 - [UTF-8 for U8GLIB](https://github.com/yhfudev/u8glib-fontutf8.git)
 - [Standalone test project for the Marlin UTF-8 language engine](https://github.com/yhfudev/marlin-fontutf8.git)

buildroot/share/scripts/createTemperatureLookupMarlin.py

 """Thermistor Value Lookup Table Generator
 
 Generates lookup to temperature values for use in a microcontroller in C format based on:
-http://en.wikipedia.org/wiki/Steinhart-Hart_equation
+https://en.wikipedia.org/wiki/Steinhart-Hart_equation
 
 The main use is for Arduino programs that read data from the circuit board described here:
-http://reprap.org/wiki/Temperature_Sensor_v2.0
+https://reprap.org/wiki/Temperature_Sensor_v2.0
 
 Usage: python createTemperatureLookupMarlin.py [options]
 

platformio.ini

 
 #
 # STM32F407VET6 with RAMPS-like shield
-# 'Black' STM32F407VET6 board - http://wiki.stm32duino.com/index.php?title=STM32F407
+# 'Black' STM32F407VET6 board - https://wiki.stm32duino.com/index.php?title=STM32F407
 # Shield - https://github.com/jmz52/Hardware
 #
 [env:STM32F407VE_black]