Need version of Thunderbird compatible with MacOS 10.13.6 High Sierra - Connection refused at UPC server

I think 115 would be compatible as it states support for 10.12 and up

Thank you David for your prompt reply. The connection was still refused by the Server - I am trying to send your the Troubleshooting App as issued from Thunderbird : Application Basics Name Thunderbird Version 115.18.0 Build ID 20241211204238 Distribution ID Update Channel esr User Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:115.0) Gecko/20100101 Thunderbird/115.18.0 OS Darwin 17.7.0 Darwin Kernel Version 17.7.0: Fri Oct 30 13:34:27 PDT 2020; root:xnu-4570.71.82.8~1/RELEASE_X86_64 OS Theme Rosetta Translated false Multiprocess Windows 0/0 Fission Windows 0/0 Enabled by default Remote Processes 0 Enterprise Policies Inactive Google Location Service Key Missing Google Safebrowsing Key Missing Mozilla Location Service Key Missing Safe Mode false Memory Size (RAM) 16,0 GB Disk Space Available 691 GB Mail and News Accounts ID Incoming server Outgoing servers Name Connection security Authentication method Name Connection security Authentication method Default? account1 (pop3) pop.hispeed.ch:110 0 passwordCleartext smtp.hispeed.ch:587 0 passwordCleartext true smtp.hispeed.ch:587 0 passwordCleartext false smtp.hispeed.ch:587 0 passwordCleartext false account2 (none) Local Folders 0 passwordCleartext account3 (pop3) pop.hispeed.ch:110 0 passwordCleartext smtp.hispeed.ch:587 0 passwordCleartext true Libraries Library Status Expected minimum version Version in use Path RNP (OpenPGP) OK 0.17.1 0.17.1.MZLA.115.18.0.botan /Applications/Thunderbird.app/Contents/MacOS/librnp.dylib Calendar Settings Home Name Value Name Type storage Disabled Username URI Refresh Interval Read-only Suppress Alarms Cache Enabled iMIP Identity id1 iMIP Disabled iMIP Account Organizer Id Force Email Scheduling Popup Alarms Supported Alarms on Invitation Supported Max Alarms Per Event Attachment Supported Max Categories Privacy State Supported Priority Supported true Event Supported Task Supported Local Time Supported UTC/GMT Supported Auto-Scheduling Supported Crash Reports for the Last 3 Days Report ID Submitted bp-6bcd107d-6b75-40a1-9996-e7c8c0261030 2 days ago Remote Processes Type Count Add-ons Name Type Version Enabled ID British English Dictionary (Marco Pinto) dictionary 4.0.9 true marcoagpinto@mail.telepac.pt English United States Dictionary dictionary 2026.9.1 true @unitedstatesenglishdictionary French spelling dictionary dictionary 6.3.1webext true fr-dicollecte@dictionaries.addons.mozilla.org German dictionary (de_CH) dictionary 20180701.1webext true de_CH@dicts.j3e.de German Dictionary dictionary 2.1 true de-DE@dictionaries.addons.mozilla.org German Dictionary (Switzerland) dictionary 2.1 true de-CH@dictionaries.addons.mozilla.org Amazon.com extension 1.1 true amazondotcom@search.mozilla.org Bing extension 1.0 true bing@search.mozilla.org DuckDuckGo extension 1.0 true ddg@search.mozilla.org Google extension 1.0 true google@search.mozilla.org Wikipedia (en) extension 1.0 true wikipedia@search.mozilla.org Language: English (GB) locale 115.18.20241211.204238 true langpack-en-GB@thunderbird.mozilla.org Language: Français (French) locale 115.18.20241211.204238 true langpack-fr@thunderbird.mozilla.org Enigmail extension 2.2.4.2 false {847b3a00-7ab1-11d4-8f02-006008948af5} Security Software Type Name Antivirus Antispyware Firewall Graphics Features Compositing WebRender Asynchronous Pan/Zoom wheel input enabled; scrollbar drag enabled; keyboard enabled; autoscroll enabled; smooth pinch-zoom enabled WebGL 1 Driver WSI Info CGL IsWebglOutOfProcessEnabled: 1 WebGL 1 Driver Renderer ATI Technologies Inc. -- ATI Radeon HD 4670 OpenGL Engine WebGL 1 Driver Version 3.3 ATI-10.4.14 WebGL 1 Driver Extensions GL_ARB_blend_func_extended GL_ARB_draw_buffers_blend GL_ARB_ES2_compatibility GL_ARB_explicit_attrib_location GL_ARB_instanced_arrays GL_ARB_internalformat_query GL_ARB_occlusion_query2 GL_ARB_sampler_objects GL_ARB_separate_shader_objects GL_ARB_shader_bit_encoding GL_ARB_shading_language_include GL_ARB_texture_buffer_object_rgb32 GL_ARB_texture_rgb10_a2ui GL_ARB_texture_storage GL_ARB_texture_swizzle GL_ARB_timer_query GL_ARB_vertex_type_2_10_10_10_rev GL_EXT_debug_label GL_EXT_debug_marker GL_EXT_texture_compression_s3tc GL_EXT_texture_filter_anisotropic GL_EXT_texture_mirror_clamp GL_EXT_texture_sRGB_decode GL_APPLE_client_storage GL_APPLE_container_object_shareable GL_APPLE_flush_render GL_APPLE_object_purgeable GL_APPLE_rgb_422 GL_APPLE_row_bytes GL_APPLE_texture_range GL_ATI_texture_mirror_once GL_NV_texture_barrier WebGL 1 Extensions ANGLE_instanced_arrays EXT_blend_minmax EXT_color_buffer_half_float EXT_float_blend EXT_frag_depth EXT_shader_texture_lod EXT_sRGB EXT_texture_compression_rgtc EXT_texture_filter_anisotropic MOZ_debug OES_element_index_uint OES_fbo_render_mipmap OES_standard_derivatives OES_texture_float OES_texture_float_linear OES_texture_half_float OES_texture_half_float_linear OES_vertex_array_object WEBGL_color_buffer_float WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_depth_texture WEBGL_draw_buffers WEBGL_lose_context WEBGL_provoking_vertex WebGL 2 Driver WSI Info - WebGL 2 Driver Renderer WebGL creation failed: * WebGL 2 requires support for the following features: transform_feedback2 (FEATURE_FAILURE_WEBGL2_OCCL) WebGL 2 Driver Version - WebGL 2 Driver Extensions - WebGL 2 Extensions - Target Frame Rate 60 GPU #1 Active Yes Vendor ID 0x1002 Device ID 0x9488 RAM 0 Diagnostics AzureCanvasBackend skia AzureContentBackend skia AzureFallbackCanvasBackend skia CMSOutputProfile