PreForm 2_20_0: https://www.mediafire.com/file/dr4hq50yaus66iw/PreForm_2_20_0.exe/file March 2019.
PreForm 3_0_0: http://www.mediafire.com/file/og2eam7qj57onyi/PreForm_3_0_0.exe/file April 2019.
PreForm 3_0_1: https://www.mediafire.com/file/jkhouchja8y6ddm/PreForm_3_0_1.exe/file April 2019.
PreForm 3_0_2: https://www.mediafire.com/file/944h2xpy8q48rga/Preform_3_0_2.exe/file July 2019.
PreForm 3_0_3: https://www.mediafire.com/file/c8r1iim5au8w1nb/Preform_3_0_3.exe/file July 2019.
PreForm 3_0_4: https://www.mediafire.com/file/brxxka4bzrxh84n/Preform_3_0_4.exe/file August 2019.
PreForm 3_0_5: https://www.mediafire.com/file/u97q41n2q6c9awy/Preform_3_0_5.exe/file August 2019.
PreForm 3_0_6: https://www.mediafire.com/file/gssgzsoyclgaprp/Preform_3_0_6.exe/file August 2019.
PreForm 3_0_7: https://www.mediafire.com/file/j95epka29yr0y7y/Preform_3_0_7.exe/file August 2019.
PreForm 3_1_0: https://www.mediafire.com/file/jpq7rd4nx4wbc6g/Preform_3_1_0.exe/file September 2019.
PreForm 3_1_1: https://www.mediafire.com/file/8vef04dmjth1u6n/Preform_3_1_1.exe/file September 2019.
PreForm 3_2_1: https://www.mediafire.com/file/w3ksngkgoebm8vn/PreForm_3_2_1.exe/file November 2019.
PreForm 3_2_2: http://www.mediafire.com/file/2a3at9xq4s1jxca/PreForm_3_2_2.exe/file November 2019.
Thanks X3msnake
PreForm 3_2_3: https://www.mediafire.com/file/focognwd8yft0s1/PreForm_3_2_3.exe/file December 2019.
PreForm 3_3_2: https://www.mediafire.com/file/7fudtmaxgio5uuk/PreForm_3_3_2.exe/file January 2020.
PreForm 3_3_3: https://www.mediafire.com/file/22w2l9tsqaqepjb/PreForm_3_3_3.exe/file February 2020.
PreForm 3_4_0: https://www.mediafire.com/file/72f2zojb7oksfgr/PreForm_3_4_0.exe/file February 2020.
PreForm 3_4_1: https://www.mediafire.com/file/0sve31xlrrn2fnu/PreForm_3_4_1.exe/file February 2020.
PreForm 3_4_2: https://www.mediafire.com/file/p3d1s0p05olefg3/PreForm_3_4_2.exe/file March 2020.
PreForm 3_4_3: https://www.mediafire.com/file/8571ya82mk3782x/PreForm_3_4_3.exe/file March 2020.
PreForm 3_4_4: https://www.mediafire.com/file/jylafyw5ie53c5k/PreForm_3_4_4.exe/file April 2020.
PreForm 3_4_5: https://www.mediafire.com/file/4cf5vl2qjo1wqit/PreForm_3_4_5.exe/file April 2020.
PreForm 3_4_6: https://www.mediafire.com/file/28kushc4gwz4lks/PreForm_3_4_6.exe/file April 2020.
PreForm 3_5_0: https://www.mediafire.com/file/xivgjcyqg9gla14/PreForm_3_5_0.exe/file May 2020.
PreForm 3_5_1: https://www.mediafire.com/file/5f10i7ln88ycjqy/PreForm_3_5_1.exe/file May 2020.
PreForm 3_5_2: https://www.mediafire.com/file/lk958jggqrhpu6x/PreForm_3_5_2.exe/file June 2020.
PreForm 3_6_0: https://www.mediafire.com/file/bnfb50geymmulp6/PreForm_3_6_0.exe/file June 2020.
PreForm 3_6_1: https://www.mediafire.com/file/zf9v21u7kfqfgsm/PreForm_3_6_1.exe/file June 2020.
PreForm 3_7_0: https://www.mediafire.com/file/mnheu2lw63hggyy/PreForm_3_7_0.exe/file July 2020.
PreForm 3_7_1: http://www.mediafire.com/file/qawio7oi7i155vl/PreForm_3_7_1.exe/file August 2020.
PreForm 3_8_0: http://www.mediafire.com/file/de5btrqmpv0m3di/PreForm_3_8_0.exe/file August 2020.
PreForm 3_8_1: http://www.mediafire.com/file/xqj0j6u8x15t0r6/PreForm_3_8_1.exe/file September 2020.
PreForm 3_9_0: http://www.mediafire.com/file/bdn31th19pl6tum/PreForm_3_9_0.exe/file September 2020.
PreForm 3_10_1: http://www.mediafire.com/file/txruybzc9zvqqr3/PreForm+3_10_1.exe/file October 2020.
PreForm 3_10_2: http://www.mediafire.com/file/j9ix29n0ip5fisc/PreForm+3_10_2.exe/file November 2020.
You can get older versions (some of them) from Formlabs website, also the Mac ones: 2014-2019 and 2020.
PreForm 3_11_0: https://www.mediafire.com/file/1qnewjj07ckaix7/PreForm+3_11_0.exe/file December 2020.
PreForm 3_11_1: https://www.mediafire.com/file/r1ybd48i42lq3un/PreForm+3_11_1.exe/file December 2020.
PreForm 3_12_0: https://www.mediafire.com/file/fivei36sv3w2sjl/PreForm+3_12_0.exe/file January 2021.
PreForm 3_12_1: https://www.mediafire.com/file/hia48m84dr3wyjc/PreForm+3_12_1.exe/file January 2021.
PreForm 3_12_2: https://www.mediafire.com/file/3x2x7bge9gca01t/PreForm+3_12_2.exe/file January 2021.
PreForm 3_12_3: http://www.mediafire.com/file/v2va7tn478u3ng9/PreForm+3_12_3.exe/file February 2021.
PreForm 3_13_0: http://www.mediafire.com/file/m2nxo9rhrp9i80f/PreForm+3_13_0.exe/file February 2021.
PreForm 3_14_0: https://www.mediafire.com/file/l5xyvbmb3q1urp8/PreForm+3_14_0.exe/file March 2021.
PreForm 3_15_0: https://www.mediafire.com/file/rls0iuz6puaoxnc/PreForm+3_15_0.exe/file April 2021.
PreForm 3_15_1: https://www.mediafire.com/file/8ve10sxmx5sfqq9/PreForm+3_15_1.exe/file April 2021.
PreForm 3_15_2: https://www.mediafire.com/file/bu2l2mc7hz6yatj/PreForm+3_15_2.exe/file April 2021.
PreForm 3_15_3: https://www.mediafire.com/file/56ug67o54iu29jb/PreForm+3_15_3.exe/file May 2021.
PreForm 3_16_0: https://www.mediafire.com/file/3w57n6t78uuca2z/PreForm+3_16_0.exe/file May 2021.
PreForm 3_17_0: https://www.mediafire.com/file/y6k09i0pfepgjn1/PreForm+3_17_0.exe/file June 2021.
PreForm 3_18_0: https://www.mediafire.com/file/f4cqncdb156scms/PreForm+3_18_0.exe/file July 2021.
PreForm 3.23.0 March 2022.
PreForm 3.23.1 March 2022.
PreForm 3.24.0 April 2022.
PreForm 3.24.1 April 2022.